SOLUTION: how do you solve y=3x y=x-4 using substitution

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Question 394304: how do you solve
y=3x
y=x-4
using substitution
Found 3 solutions by TeishaRenee, richard1234, Alan3354:
Answer by TeishaRenee(14)   (Show Source):
You can put this solution on YOUR website!
take the second equation and plug it into the first one after you set it equal to x.
so y+4=x then plug it into the first equation.
y=y+4-4
then 4-4=0
so your answer would be y=y which would make it be no solution.
your answer is NO SOLUTION!!!
hope i helped, i would be happy to do more for you if you need them. email me trdl@msn.com

Answer by richard1234(7193)   (Show Source):
You can put this solution on YOUR website!
Seems like there is a solution. Substituting 3x into the second equation we get

3x = x - 4

x = -2

Since y = 3x, then y = 3(-2) = -6. It also satisfies the second equation.

Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website!
how do you solve
y=3x
y=x-4
using substitution
----------
Sub 3x for y in the 2nd eqn
3x = x-4
2x = -4
x = -2
--------
y = -6