Question

Solve the following system of equations.
x + y = 15
x – y = -19
A. (2, 17)
B. (-2, -17)
C. (-2, 17)
D. (5, 5)

Answer 1

need help finding an answer

Answer 2

Add the two equations together and what do you get?

Answer 3

x + y = 15
x – y = -19
Luckily, you don't have to use any form of substitution/elimination to solve this. Basically just add them together and divide. :D
x + y = 15
x – y = -19
x +x = 2x
y -y = 0
15 - 19 = -4
We're left with:
2x = -4
Divide each side by 2.
x = -2 <--- We can plug this into one of the original equations to find y.
x + y = 15
Plugging in x.
-2 + y = 15
Add 2 to each side.
y = 17
Solution: (-2, 17) <--- Answer. (:

Answer 4

You can also plug the solution in to see if it works. (-2, 17)
x + y = 15
x – y = -19
-2 + 17 = 15
15 = 15 Yes.

x - y = -19
-2 - 17 = -19
-19 = -19 Yes.