Question

The length of a rectangular birthday party invitation is 1 inch less than twice its width. The area of the invitation is 15 square inches.

Answer 1

Step-by-step explanation:

The area of a rectangle is length times width.

Let width = x

Let length = 2x - 1

Area = 21 in2

Using these variables, set up the equation for area.

x(2x - 1) = 21

Solve the equation for x.

2x2 - x = 21

Subtract 21 on both sides of the equation.

2x2 - x - 21 = 0

Factor using FOIL, if possible.

(2x - 7)(x + 3) = 0

Set the factors equal to zero and solve for x.

2x - 7 = 0 and x + 3 = 0

x = 7/2 x = -3

x = 3.5

Since we cannot accept a negative value for dimensions, we accept the positive value of x:

x = 3.5

Therefore,

Length = 2(3.5) - 1

I leave it to you to complete the calculation.

hope it helps you