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AllieLovesSoccer: 4 months ago

How to do the substitution method? The problem is
x=16-4y
3x+4y=8

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Answer 1

FaithfulReader: 4 months ago

Are x=16-4y and 3x+4y=8 two different equations?
If so, then Then you will plug (substitute) one into the other.
Take x=16-47.
Put it in for x in your other equation.
3(16-4y)+4y=8
48-12y+4y=8
48-8y=8
-8y+48 -48 = 8-48
-8y=-40
Divide both sides by -8.
y=5
Then you will plus 5 in for y in the other equation to find x.
x=16-4(5)
x=16-20
x=-4
Your solution point is (-4,5)

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Answer 2

russianrespect: 4 months ago via iPhone | Last edited at 11:41AM on 1/7/2013

You replace your first equation with the second equation's x for example
3 ( 16-4y)+4y=8
then you multiplie 3 by 16 and -4
then you isolate the y
and you treat is as a normal equation
hope i helped !

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Answer 3

alsubhi: 4 months ago via iPhone | Last edited at 11:51AM on 1/7/2013

4y=16-x
4y=8?3x
Do the subtraction the result is
0=8+2x then
2x=-8
x=-8/2
x=-4
Substitute x in the equation
4y=16-(-4)
4y=20 then
y=20/4
y=5
sorry I thought you want to solve it by subtraction.

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Answer 4