Answer:
A: 5x^2 + 42x + 16
B: 12x + 20
C: 351 units
Step-by-step explanation:
A: (5x + 2) * (x + 8) is the same as x(5x + 2) + 8(5x + 2). You just need to solve and simplify that for the area:
x(5x + 2) + 8(5x + 2)
= 5x^2 + 2x + 40x + 16
= 5x^2 + 42x + 16
B: You need to do 2l + 2w, or 2(5x + 2) + 2(x + 8):
2(5x + 2) + 2(x + 8)
= 10x + 4 + 2x + 16
= 12x + 20
C: You can either replace the x in the equation with 5 or replace the x in the figure itself with 5. I will replace the one in the figure with 5 because it is a lot easier:
(5(5) + 2) * (5 + 8)
= 27 x 13
= 351 units
