Once simplified, which of the expressions below is equal to −3x−39? Select all that apply. A) 6(2x–5)–15x–9
B) −3(x+13)
C) 6(23x–5)−7x–9
D) 3x(x–3)

It would be B. When you apply the distributive property (which is multiplying the outside integer on the outside of the parenthesis by the ones one the inside) you get -3 times x, which is -3x, and -3 times 13, which is -39 (it is negative because the positive times the negative is negative). This results in the solution -3x-39.