HELP ME PLEASE‼️‼️‼️‼️‼️

Answer:
a. 8
b. 248
Step-by-step explanation:
first, find the derivative:
-2x^2 + 32x + 120
= -4x + 32
then, have that equal 0
-4x + 32 = 0
32 = 4x
8 = x
answer a: 8
plug in answer a into the original equation
-2(8)^2 + 32(8) +120
answer b: 248