Question

5x+4y=-15
-3x+y=26

Answer 1

http://www.wolframalpha.com/input/?i=5x%2B4y%3D-15%2C+-3x%2By%3D26

Answer 2

x=-7 y=5

Answer 3

5x+4y=-15 --------------(1)
-3x+ y=26 --------------(2)

multiply (2) by -4 and add to (1)

5x + 4y = -15
12x - 4y = -104

we get
17x = - 119
x = -119/17
x = -7

substituting x = -7 in (1), we get
5(-7) + 4y = -15
-35 + 4y = -15
4y = -15 + 35
y = 20/4
y = 5

so solution set (x,y) = (- 7 , 5)