Answer:
Known: perimeter = 530 feet.
Known: width = length - 3 feet
Known: it's a rectangle so
perimeter = 2×width + 2×length
Unknown: length and width
Equation:
530 feet = 2×width + 2×length
Substitute for width:
530 feet = 2×(length - 3 feet) + 2×length
If you insist on one character variable names and no units,
530 = 2(L-3) + 2L = -6 + 4L
536 = 4L
L = 134
530 feet = 2×length - 6 feet + 2×length
530 feet = 4×length - 6 feet.
(530 + 6) feet = 4×length
536 feet = 4×length
length = (536/4) feet = 134 feet
width = length - 3= 131 feet
The length of the rectangle is 134 feet.
The width of the rectangle is 131 feet.
Check: 2×134 + 2×131 = 268+262 = 530 feet
