16x - 3(4x + 5) = 2x + 9
We, first open the brackets
16x - 3(4x) - 3(5) = 2x + 9
16x - 12x - 15 = 2x + 9
We, then, bring like terms together.
16x - 12x - 2x = 15 + 9
2x = 24
We can divide by 2 on either sides to isolate and find value of x

2 and 2 cancels out
x = 12