Kitkat1
  • Kitkat1
Medal for best answer!!!!! Given the system of equations presented here: 4x + y = 4 2x + 7y = 28 Which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? Multiply the second equation by −1 to get −2x − 7y = −28 Multiply the second equation by −4 to get −8x − 28y = −112 Multiply the first equation by −7 to get −28x − 7y = −28 Multiply the first equation by −2 to get −8x − 2y = −8
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
schrodinger
  • schrodinger
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
Kitkat1
  • Kitkat1
@whpalmer4 can u help me?
Kitkat1
  • Kitkat1
Does anybody know this?
DanJS
  • DanJS
you want to multiply one of the equations by some constant value, so that when you add them together, one variable will add to zero

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

Kitkat1
  • Kitkat1
Multiply by -2?
DanJS
  • DanJS
notice if you multiply the second by (-2), you get 4x + y = 4 -4x -14 y = -56 -----------------
DanJS
  • DanJS
then when you add the two equations, the x term will drop out (-4 + 4) = 0x
DanJS
  • DanJS
you see that
Kitkat1
  • Kitkat1
Yes I do so the right answer is D?
DanJS
  • DanJS
no, that example i just did multiplied the second by -2
Kitkat1
  • Kitkat1
Okay but how do I find the answer?
DanJS
  • DanJS
so, instead, how would you make the Y term drop out
Kitkat1
  • Kitkat1
Multiply by -1?
DanJS
  • DanJS
try -7 times the first equation (-7)(4x + y = 4 ) 2x + 7y = 28
DanJS
  • DanJS
gives -28x - 7y = -28 2x + 7y = 28 ------------------
DanJS
  • DanJS
adding equation 1 to equation 2 now, the y term goes to zero -26x + 0y = 0
DanJS
  • DanJS
so -26x = 0 x=0 plug into either to get the y
DanJS
  • DanJS
x=0 , y=4 to solve systems of linear eqn you can - muyltiply equations by constants add equations together switch order of equations
Kitkat1
  • Kitkat1
I ended up with 43=28 when plugged into the 2nd equation I don't know If I done it wrong.
Kitkat1
  • Kitkat1
I dont know what I am doing that I dont get the answer
DanJS
  • DanJS
start system 4x + y = 4 2x + 7y = 28 --------------- multiply first equation through by -7 to get -28x - 7 y = -28 2x + 7y = 28 -------------------
Kitkat1
  • Kitkat1
So I plug -7 to each of those equations the positive and the negative one?
DanJS
  • DanJS
adding the equations together eliminates y, what the instructions say to do -28x + 2x - 7y + 7y = -28 + 28 -26x =0
DanJS
  • DanJS
no, multiply each term in the first equation by a -7
Kitkat1
  • Kitkat1
Okay so the answer is 3?
DanJS
  • DanJS
multiply first equation through by -7 to get , second equation is not changed -28x - 7 y = -28 2x + 7y = 28 -------------------
Kitkat1
  • Kitkat1
Yes so the 3rd choice
DanJS
  • DanJS
th epoint of that was to eliminate the y variable when you add the two equations together
DanJS
  • DanJS
-26x = 0
DanJS
  • DanJS
so x=0
DanJS
  • DanJS
and if you want to find y, plug x=0 into either of the equations
DanJS
  • DanJS
4x + y = 4 2x + 7y = 28
DanJS
  • DanJS
y = 4, should be the same in both , or you messed up
Kitkat1
  • Kitkat1
Yes I got that so 4=4
DanJS
  • DanJS
x = 0, so 4(0) + y = 4 ----->y = 4 2(0) + 7y = 28 -----7y = 28 ---->y = 4 same y=4 from both equations when x=0
Kitkat1
  • Kitkat1
Okay I dont get whats the answer should be
DanJS
  • DanJS
another answer they dont include, was what i did at the very start, i figured y first, multiplied second equation by -2, so when added the x term goes away
Kitkat1
  • Kitkat1
So which option should I pick then?
DanJS
  • DanJS
The third one, we multiplied the fisrt by -7 to get that Which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? -when combined means when you add them together, one variable will go to zero, like the -7y + 7y = 0y , y is eliminated
Kitkat1
  • Kitkat1
Okay can you help me with one more question?
DanJS
  • DanJS
just takes a few practice probs to get it down,
DanJS
  • DanJS
sure i can do one more
Kitkat1
  • Kitkat1
Determine the solution to f(x) = g(x) using the following system of equations f(x) = 5.5x − 13 g(x) = −5x + 18.5 x = 1 x = 2 x = 3 x = 4
Kitkat1
  • Kitkat1
I remember doing this but cant remember how
DanJS
  • DanJS
both f(x) and g(x) are functions on the XY plane. when f(x) = g(x), the two functions intersect at the same point (x,y)
Kitkat1
  • Kitkat1
Can u show me how to solve it?
DanJS
  • DanJS
set them equal f(x) = g(x) 5.5x - 13 = -5x + 18.5
Kitkat1
  • Kitkat1
Then?
DanJS
  • DanJS
add 5x to both sides
Kitkat1
  • Kitkat1
like this 5.5x - 13 - -5x +18.5 5x 5x
DanJS
  • DanJS
10.5x - 13 = 18.5 add 13 both sides 10.5x = 31.5
DanJS
  • DanJS
divide both sides by 10.5 1x = 31.5 / 10.5
Kitkat1
  • Kitkat1
Okay then divide by 10.5
DanJS
  • DanJS
x = 3
DanJS
  • DanJS
yep, the goal is to isolate x by itself
Kitkat1
  • Kitkat1
Okay thank you very much for the help!
DanJS
  • DanJS
no prob, anytime

Looking for something else?

Not the answer you are looking for? Search for more explanations.