9X+y=2

-4X-y=17

2 answers

use elimination method to solve it.
9 x + y = 2
-4 x- y = 17 Add
______________

9 x + ( - 4x ) + y + ( - y ) = 2 + 17

9 x - 4 x + y - y = 2 + 17

5 x + 0 = 19

5 x = 19 Divide both sides by 5

x = 19 / 5 = 3.8

9 x + y = 2

9 * 19 / 5 + y = 2

171 / 5 + y = 2

y = 2 - 171 / 5

y = 10 / 5 - 171 / 5

y = - 161 / 5

y = - 32.2