SOLUTION: Can you use either elimination or substitution (both would be nice but not necessary!!!)Thank you! 5x-2y=-11 3x+2y=-9 When I tried for elimination I got: 5x-2y=-11 +

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Can you use either elimination or substitution (both would be nice but not necessary!!!)Thank you! 5x-2y=-11 3x+2y=-9 When I tried for elimination I got: 5x-2y=-11 +       Log On


   

Question 882641: Can you use either elimination or substitution (both would be nice but not necessary!!!)Thank you!
5x-2y=-11
3x+2y=-9
When I tried for elimination I got:
5x-2y=-11
+ 3x+2y=-9
____________
8x=-20
x=-5/2
Then I substituted -5/2 for 'x' in the first equation;
5(-5/2)+2y=-11
-25/2+2y=-11
2y=3/2
y=3/4
but when I tried with substitution I got:
2y=11+5x
y=11/2+5/2
y=16
It would be lovely if you could help me with this!!
Thank you again and best of luck!!!
-Kristie
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
You can use substitution only; elimination only; or a mix of elimination and substitution. You will have the same correct solution regardless which method you use.

Your given system:
5x-2y=-11
3x+2y=-9
Perfectly ready for Elimination Method to start, to eliminate y.

Just sum the left members and sum the right members:
5x-2y%2B3x%2B2y=-11%2B%28-9%29
5x%2B3x-2y%2B2y=-20
8x=-20
x=-20%2F8=-10%2F4
highlight%28x=-5%2F2%29
-
Substitute this x for either equation of the system to find the value for y.
2y=-3x-9
y=-%283%2F2%29x-9%2F2
y=-%283%2F2%29%2A%28-5%2F2%29-9%2F2
y=15%2F4-18%2F4
highlight%28y=-%283%2F4%29%29
-

CHECK: Does the solution work in the original system?
5x-2y=-11
5%28-5%2F2%29-2%28-3%2F4%29=-11?
-25%2F2%2B6%2F4=-11
-50%2F4%2B6%2F4=-11
-44%2F4=-11 TRUE.

3x+2y=-9
3%28-5%2F2%29%2B2%28-3%2F4%29=-9?
-15/2-6/4=-9
-30/4-6/4=-9
-36%2F4=-9 TRUE.

The solution really IS highlight%28x=-5%2F2%29 AND highlight%28y=-3%2F4%29.

If you found disagreements about your results, check for mistakes.
(You made a sign mistake......)