SOLUTION: Solve the system by the substitution method: x= 4y + 7 7x + y= 20 what is x and y?

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Question 188025This question is from textbook Saxon
: Solve the system by the substitution method:
x= 4y + 7
7x + y= 20
what is x and y? This question is from textbook Saxon

Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!


Given;
x= 4y + 7, EQN 1
7x + y= 20, EQN 2

Substitute EQN 1 in EQN 2:
7%28highlight%284y%2B7%29%29%2By=20
28y%2B49%2By=20
29y=20-49=-29---->cross%2829%29y%2Fcross%2829%29=cross%28-29%291%2Fcross%2829%29
red%28y=-1%29, substitue in EQN 1
x=4%28-1%29%2B7=-4%2B7=red%283%29
Answer (x,y)=(3,-1)

We'll see graph:
==> RED, EQN 1 ;; GREEN, EQN 2

Thank you,
Jojo