solve by elimiation
2r - 9s = -17
9r + 2s = 51
Multiply your first equation by -9 and the second equation by 2.
-18r + 81s = 153
18r + 4s = 102
Next, add those two equations to eliminate the "r" variable.
85s = 255
Take it from there
2r - 9s = -17
9r + 2s = 51
-18r + 81s = 153
18r + 4s = 102
Next, add those two equations to eliminate the "r" variable.
85s = 255
Take it from there