help asap Please show working​

Answer:
(a) -12
(b) 37
(c) -840
Step-by-step explanation:
We simply have to plug in the values for each expression.
2 + -3(3) - 5 = 2 + -9 - 5 = -7 - 5 = -12
5(2) - 4(-3) + 3(5) = 10 - -12 + 15 = 10 + 12 + 15 = 22 + 15 = 37
7(2^3)(-3)(5) = 7(8)(-15) = 56(-15) = -840