SOLUTION: solve 2x+y=-1 y=x+8 using the substitution method

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Question 773363: solve 2x+y=-1
y=x+8
using the substitution method
Answer by Tatiana_Stebko(1539) About Me  (Show Source):
You can put this solution on YOUR website!
system%282x%2By=-1%2C+y=x%2B8%29
Substitute y=x%2B8 into the first equation of the system
2x%2B%28x%2B8%29=-1
2x%2Bx%2B8=-1
3x=-9
x=-3
Substitute x=-3 into +y=x%2B8
y=-3%2B8
y=5
system%28x=-3%2C+y=5%29 - the solution of the system
Check the answer
system%282%2A%28-3%29%2B5=-1%2C+5=-3%2B8%29
system%28-1=-1%2C+5=5%29 - correct
Answer: (-3, 5)