Answer:
Width W = 7 m
Length L = 9 m
Step-by-step explanation:
Area of a rectangle = L * W
Area = 63 m²
L = 3W - 12
Area = L * W
66 = (3W - 12) * W
63 = 3W² - 12W
3W² - 12W - 63 = 0 ( solve W by using quadratic equation)
-(-12) ± √ -12² - 4 * 3 * (-63)
W = -------------------------------------------
2 * 3
W = 7 ; W = - 3
therefore use W = 7 m
solve for L:
L = 3W - 12
L = 3(7) - 12
L = 9 m
check:
Area = L * W
63 = 9 * 7
63 = 63 ----- OK
