3x - y = 8...add y to both sides, subtract 8 from both sides
3x - 8 = y
so we sub 3x - 8 in for y in the other equation
2x + 3y = 9
2x + 3(3x - 8) = 9
2x + 9x - 24 = 9
2x + 9x = 9 + 24
11x = 33
x = 33/11
x = 3
3x - 8 = y
3(3) - 8 = y
9 - 8 = y
1 = y
so ur solution is (3,1) <==