Step-by-step explanation:
length = 2×width + 6
84 = 2×length + 2×width
now using the first in the second equation :
84 = 2×(2×width + 6) + 2×width = 4×width + 12 + 2×width
84 = 6×width + 12
72 = 6×width
width = 12 cm
length = 2×width + 6 = 2×12 + 6 = 24 + 6 = 30 cm
Answer:
9x^2 - 36x + 36 sq. ft. (the first option).
Step-by-step explanation:
Area of a square of side d = d^2.
So area of this square = (3x - 6)^2
= (3x - 6)(3x - 6)
= 3x(3x - 6) - 6(3x - 6)
= 9x^2 - 18x - 18x + 36
= 9x^2 - 36x + 36 sq ft.
