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anonymous
 one year ago
Can someone set up this question for me? I am really struggling/:
5x  2y + 3z = 23
x  2y + 2z = 5
10x + y  4z = 11
Q1 choose a fav variable
A1
Q2 pick a pair of equations, eliminate the fav variable
A2
Q3 pick another pair, eliminate that same fav
A3
Q4 now you have only 2 variables in 2 equations, like a+b=7 & a2b=13
A4
Q5 pick a second fav
A5
Q6 add equations together and eliminate it
A6
Q7 solve for second fav
A7
Q8 sub second fav into equation and find last variable
A8
anonymous
 one year ago
Can someone set up this question for me? I am really struggling/: 5x  2y + 3z = 23 x  2y + 2z = 5 10x + y  4z = 11 Q1 choose a fav variable A1 Q2 pick a pair of equations, eliminate the fav variable A2 Q3 pick another pair, eliminate that same fav A3 Q4 now you have only 2 variables in 2 equations, like a+b=7 & a2b=13 A4 Q5 pick a second fav A5 Q6 add equations together and eliminate it A6 Q7 solve for second fav A7 Q8 sub second fav into equation and find last variable A8

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phi
 one year ago
Best ResponseYou've already chosen the best response.0How about starting with y and the first two equations 5x  2y + 3z = 23 x  2y + 2z = 5 subtract the bottom equation from the top equation can you do that ?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@phi 4x + 5z = 28 ??

phi
 one year ago
Best ResponseYou've already chosen the best response.0the easiest (or at least likely to make mistakes) is to first multiply the 2nd equation by 1 that means multiply both sides and all terms by 1 1*(x  2y + 2z ) = 1*5 distribute the 1. we get \[1\cdot x + 1\cdot2y + 1\cdot2z = 5\\ x+2y 2z = 5 \] now we add, term by term the top equation and this new equation 5x  2y + 3z = 23 x+ 2y  2z = 5 what do you get ?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@phi 6x + z = 28 now what?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I dont know what to do now for Q5Q8 ?? :(

phi
 one year ago
Best ResponseYou've already chosen the best response.0ok that looks good. now pick the 2nd and 3rd equations x  2y + 2z = 5 10x + y  4z = 11 and we again want to "get rid of y" multiply the second equation in that pair by 2 (all terms) can you do that ?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0multiply just 10x + y  4z = 11 by 2 ?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0what do i do with the other? @phi

triciaal
 one year ago
Best ResponseYou've already chosen the best response.0You will add it to the new equation you get when you do the multiplication

triciaal
 one year ago
Best ResponseYou've already chosen the best response.0so go ahead and do the multiplication and show what you get

triciaal
 one year ago
Best ResponseYou've already chosen the best response.0sure he will be back he is going through all the steps with you

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0thank you @triciaal is that equation correct?

triciaal
 one year ago
Best ResponseYou've already chosen the best response.0not exactly watch your signs

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so now that i have done that, what do i put into this? Q5 pick a second fav A5 Q6 add equations together and eliminate it A6 Q7 solve for second fav A7 Q8 sub second fav into equation and find last variable A8

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0like how do i explain and set that all up into these questions?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0because I have this so far.. does it look correct? 5x  2y + 3z = 23 x  2y + 2z = 5 10x + y  4z = 11 Q1 choose a fav variable A1 y Q2 pick a pair of equations, eliminate the fav variable A2 5x  2y + 3z = 23  x  2y + 2z = 5 = 4x + 5z = 28 Q3 pick another pair, eliminate that same fav A3 6x + z = 28 Q4 now you have only 2 variables in 2 equations, like a+b=7 & a2b=13 A4 4x + 5z = 28 & 6x + z = 28

phi
 one year ago
Best ResponseYou've already chosen the best response.0we are doing Q2 we picked the 2nd and 3rd equations x  2y + 2z = 5 10x + y  4z = 11 . You multiplied the 2nd of that pair by 2. you now have the equations x  2y + 2z = 5 20x + 2y  8z = 22 now add those two equations. what do you get?

phi
 one year ago
Best ResponseYou've already chosen the best response.0oops , we are doing Q3 Q2 is what we got from the first two equations, up above.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so Q3 is 6x + z = 28 ??

phi
 one year ago
Best ResponseYou've already chosen the best response.0FYI the answer for Q2 Here are the steps 5x  2y + 3z = 23 x  2y + 2z = 5 < multiply by 1 and add to the top equation. we get 6x + z = 28

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yeah! that is what I did..

phi
 one year ago
Best ResponseYou've already chosen the best response.0for Q3 we picked the 2nd and 3rd equations x  2y + 2z = 5 10x + y  4z = 11 . You multiplied the 2nd of that pair by 2. you now have the equations x  2y + 2z = 5 20x + 2y  8z = 22 now add those two equations. what do you get?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0i got 19x  6z = 17

phi
 one year ago
Best ResponseYou've already chosen the best response.0ok, that is the last part of the answer for Q3

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Q1 choose a fav variable A1 y Q2 pick a pair of equations, eliminate the fav variable A2 5x  2y + 3z = 23  x  2y + 2z = 5 = 4x + 5z = 28 Q3 pick another pair, eliminate that same fav A3 x  2y + 2z = 5 + 20x + 2y  8z = 22 = 19x  6z = 17

phi
 one year ago
Best ResponseYou've already chosen the best response.0for Q4 we have these equations 6x + z = 28 19x  6z = 17 for Q5, pick z as the "favorite variable"

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0did i put it in those answers correctly so far?

phi
 one year ago
Best ResponseYou've already chosen the best response.0for Q6 6x + z = 28 < multiply all terms by 6 19x  6z = 17

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Q4 now you have only 2 variables in 2 equations, like a+b=7 & a2b=13 A4 6x + z = 28 & 19x  6z = 17 Q5 pick a second fav A5 z Q6 add equations together and eliminate it A6 6x + z = 28 + 19x  6z = 17 = 25x  5z = 45

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0it said add equations together ?

phi
 one year ago
Best ResponseYou've already chosen the best response.0unless there is a typo in the original equations, we can't just add them first we multiply the first one by 6 (this will give us a 6z term that will cancel the 6z in the other equation)

phi
 one year ago
Best ResponseYou've already chosen the best response.0now we can add the equations

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok..which equations?

phi
 one year ago
Best ResponseYou've already chosen the best response.019x  6z = 17 36x + 6z = 168

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Q5 pick a second fav A5 z Q6 add equations together and eliminate it A6 36x + 6z = 168 + 19x  6z = 17 Q7 solve for second fav A7 55x = 185

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0is this correct? @phi

phi
 one year ago
Best ResponseYou've already chosen the best response.0except 168 + 17 is not 185

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0now what about for Q8 ?

phi
 one year ago
Best ResponseYou've already chosen the best response.0yes, so 55x= 185 divide both sides by 55 \[ x =  \frac{185}{55}=  \frac{37}{11} \]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.05x  2y + 3z = 23 x  2y + 2z = 5 10x + y  4z = 11 Q1 choose a fav variable A1 y Q2 pick a pair of equations, eliminate the fav variable A2 5x  2y + 3z = 23  x  2y + 2z = 5 = 4x + 5z = 28 Q3 pick another pair, eliminate that same fav A3 x  2y + 2z = 5 + 20x + 2y  8z = 22 = 19x  6z = 17 Q4 now you have only 2 variables in 2 equations, like a+b=7 & a2b=13 A4 6x + z = 28 & 19x  6z = 17 Q5 pick a second fav A5 z Q6 add equations together and eliminate it A6 36x + 6z = 168 + 19x  6z = 17 x= 37/11 Q7 solve for second fav A7 55x = 185 Q8 sub second fav into equation and find last variable A8

phi
 one year ago
Best ResponseYou've already chosen the best response.0yes, but when you show the equations, you should put them on separate lines something like this: A6 36x + 6z = 168 + 19x  6z = 17  55x = 185 x = 185/55 = 37/11

phi
 one year ago
Best ResponseYou've already chosen the best response.0for A7, use 19x  6z = 17 replace x with 37/11

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0lol i am confused now ... can u copy and paste that Q&A format in the beginning so i can see?

phi
 one year ago
Best ResponseYou've already chosen the best response.0you wrote Q6 add equations together and eliminate it A6 36x + 6z = 168 + 19x  6z = 17 x= 37/11 it would be clearer if you wrote it as A6 36x + 6z = 168 + 19x  6z = 17  55x = 185 x = 185/55 = 37/11

phi
 one year ago
Best ResponseYou've already chosen the best response.0for A7, use 19x  6z = 17 replace x with 37/11

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0just for Q8 idk what to put

phi
 one year ago
Best ResponseYou've already chosen the best response.0first we have to do Q7 Q7 solve for second fav

phi
 one year ago
Best ResponseYou've already chosen the best response.0to do that we start with one of the equations from A4 for example, we can use 6x + z = 28 x is 37/11 replace x with that number. we want to find what z is
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