Solve for x and y

-2x-y=-9

5x-2y=-9

we use equation 1 first.

-2x - y = - 9

-y = - 9 + 2x

y = 9 - 2x

We substitute value of y in equation 2

5x - 2 (9 - 2x) = - 9

5x - 18 - 4x = - 9

5x - 4x = - 9 + 18

x = 18 - 9

x = 9

We now find the value of y

-2x - y = - 9

-2 (9) - y = - 9

-18 - y = - 9

-y = - 9 + 18

y = 9 - 18

y = - 9