5(x + 3) - 7x
We will use the distbutive property at first
5(x + 3) = 5(x) + 5(3) ========= distrbutive property
5(x + 3) = 5x + 15
5(x + 3) - 7x = 5x + 15 - 7x
Now we will add the like terms
5(x + 3) - 7x = (5x - 7x) + 15 ======= commutative property
5(x + 3) - 7x = -2x + 15