A rectangular garden has a length of x + 2 ft. and a width of x + 8 ft. What must x be in order for the garden to have an area of 91 sq. ft.?

5 ft

Step-by-step explanation:

Our equation can be (x + 8)(x + 2) = 91. Now we solve:

(x + 8)(x + 2) = 91

x^2 + 2x + 8x + 16 = 91    expand

x^2 + 10x + 16 = 91           simplify

x^2 + 10x - 75 = 0            subtract 91 from both sides

(x + 15)(x - 5) = 0               factor

x + 15 = 0              x - 5 = 0

x -15                    x = 5

x can't equal -15 because you cannot have negative feet, so x = 5 feet