Answer:
The amount with which she should increase the length and the with of the sandbox is 2 feet each
Step-by-step explanation:
The dimensions of Melissa's rectangular box are;
Width of the box = 4 feet
Length of the box = 8 feet
The total area of the new sandbox, A = 60 square feet
Let 'x' represent the amount by which she increases the width and lengths of sides that not against the fence, we have;
The area of the new sandbox, A = The new length × The new width
A = 60 ft.²
The new length = 8 + x
The new width = 4 + x
∴ A = 60 = (8 + x) × (4 + x) = x² + 12·x + 32
60 = x² + 12·x + 32
60 - 60 = 0 = x² + 12·x + 32 - 60
∴ x² + 12·x - 28 = 0
(x + 14)·(x - 2) = 0
x = -14 or x = 2
Therefore, the amount she can increase the width and lengths of sides that not against the fence to have make a new sandbox with an area of 60 ft.² is, x = 2 feet
The amount of increase of the length and the width of the sandbox, x = 2 feet each.
