Answer:
Length L = 17 ft.
Width W = 4 ft
Step-by-step explanation:
Area of a rectangle = L * W
Area = 68 ft²
W = 2L - 30
Area = L * W
68 = L * (2L - 30)
68 = 2L² - 30L
2L² - 30L -68 = 0 ( solve L by using quadratic equation)
-(-30) ± √ -30² - 4 * 2 * (-68)
L = -------------------------------------------
2 * 2
L = 17 ; L= - 2 therefore use L = 17 ft.
solve for W:
W = 2L - 30
W = 2(17) - 30
W = 34 - 30
W = 4 ft
check:
Area = L * W
68 = 17 * 4
68 = 68 ----- OK
