SOLUTION: what is the substitution for 4y+4x=40 y=3x-30

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Question 267714: what is the substitution for
4y+4x=40
y=3x-30
Answer by dabanfield(803) About Me  (Show Source):
You can put this solution on YOUR website!
what is the substitution for
1.) 4y+4x=40
2.) y=3x-30
Based on 2.) we can substitute 3x-30 for y in equation 1.) giving:
4*(3x-30)+4x = 40
12x-120+4x = 40
16x = 160
x = 10
Now we can substitute 10 for x in equation 2.) to determine y.