you distribute the 3 to each value inside the parenthesis so it becomes 3x + 3 - 2x = -6
then combine the like terms by doing 3x-2x= x, and bringing the 3 to the other side of the equation by subtracting so the whole problem would then read, x=-9
to check you would plug in the -9 wherever there is an x.
3(-9 + 1) - 2(-9) = -6
3(-8) - 2(-9) = -6
-24 + 18 = -6
-6 = -6