SOLUTION: SOLVE BY SUBSTITUTION X+y=0 X-2y+9=0 I did... X+y=0 and I subtracted x from both side and got Y=0 Then I substituted the (0) into the second equation x-2(0)+9=0 >>x-

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Question 949207: SOLVE BY SUBSTITUTION
X+y=0
X-2y+9=0
I did... X+y=0 and I subtracted x from both side and got Y=0
Then I substituted the (0) into the second equation x-2(0)+9=0 >>x-2+9=0 which I then combined like terms and got x+7=0 and I subtracted 7 from both sides and got X=-7
Please help I am stuck. And please show how to check my answers
Thank you
Answer by rothauserc(4718) (Show Source):
You can put this solution on YOUR website!
We are given
X +y = 0
X -2y +9 = 0
from the first equation, we have x = -y by subtraction y from both sides of =
substitute for x in second equation and we get
-y -2y +9 = 0
-3y = -9
subtract 9 from both sides of =
y = 3 and from first equation x = -3
now substitute for x and y in the second equation
-3 -(2*3) +9 = 0
-3 -6 +9 = 0
-9 +9 = 0
0 = 0
our answers for x = -3 and y = 3, check
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