Step-by-step explanation:
Given that,
Length, l = (3d+2) m
Width, b = (d+5) m
(a) Perimeter of the rectangle,
P = 2(l+b)
P = 2(3d+2+d+5)
= 2(4d+7)
P = 8d+14
(b) If P = 30 cm.
8d+14 = 30
8d = 16
d = 2
(c) l = (3(2)+2) = 8 m
b = (2+5) = 7 m
The area of this rectangle,
A = lb
A = 8×7
A = 56 cm²
Hence, this is the required solution.