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anonymous
 5 years ago
y=4x
x+y=5
anonymous
 5 years ago
y=4x x+y=5

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sandra
 5 years ago
Best ResponseYou've already chosen the best response.0this is a classic "substituion" problem

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0the idea is that you want to take the value of a variable from one equation, and "substitute" that into the other

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0since you have two unknowns, you need two equations  which you have

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0so let's take y=4x and substitute it into the second equation

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0so x+y = 5 becomes x + (4x) = 5 (I just replaced y in the second equation with what the first equation asserted y to be)

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0that is called subsitution

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0so x+4x =5, 5x=5, and now divide both sides by 5 for the answer

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0now that you have x, you can substitute that back into either equation to get the value of y

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0so x+y = 5, and I know that x=1. so 1+y=5, 11+y = 51, y=4 (subtract 1 from both sides)

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i got up to x=1 then got confused on Y

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0well, think of x=1 as just another piece of information you now have, along with the original equations

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0so if x+y = 5 , and I already know x=1, then I can substitute the value of x in that first equation with what I know to be true

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0you can always check your work at the end of these problems too

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0plug in 4x for y x+4x=5 5x=5 5 divided by 5 = 1

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0so our guess is that x = 1, and y = 4

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0if you stick those back into the original equations, do they hold true?

sandra
 5 years ago
Best ResponseYou've already chosen the best response.0if they do, then you know you did it right
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