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-

Algebra.Com
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
*******

RELATED QUESTIONS

Here's what i did: the equation is 2-y=x-6. I'm trying to get it into standard form of a (answered by uma)
2y+x=0 x=y+9 Solve by substitution. (answered by Maths68)
sorry but i'am not sure what this kind of problem is what is x? sqrt (3x+1)+ sqrt... (answered by Alan3354,stanbon)
Determine how many solutions exist. Use either elimination or substitution to find the... (answered by mananth)
2y(cubed)+y(squared)=3y i subtracted 3y and got 2y(cubed)+y(squared)-3y=0 then i... (answered by richwmiller)
How do I find X and Y by using substitution? 2x + y = 0 x - 3y =... (answered by Techpriest)
This is the equation: 6x=y, and i'm trying to get it into standard form. Is it all right... (answered by uma)
I need help on knowing how to solve linear systems in form of fractions. the problem: (answered by user_dude2008,amoresroy)
find the x and y intercept for the given equation: y = 12 x -10 i used a 0 in the... (answered by themasterofcircuits)