Calculate X: Rectangle Area = 22x with Side Length (x+8)

Question

The area of the rectangle below is equal to 22x x .

Calculate x x .

x+8x+8x+8

Video Solution

Solution Steps

00:00 Determine the value of X
00:03 Apply the formula for calculating the area of a rectangle (length x width)
00:13 Substitute in the relevant values according to the given data and proceed to solve for X
00:32 Open the parentheses and multiply 0.5X by the 2 factors
00:57 Arrange the equation so that we have 0 on one side
01:14 Take half X out of the parentheses
01:26 Determine the solution options for X
01:37 X must be greater than 0 given that it's a length of a side
01:40 This is the solution

Step-by-Step Solution

The area of a rectangle is equal to its length multiplied by its width.

Let's write out the known data:

22x=12x×(x+8) 22x=\frac{1}{2}x\times(x+8)

22x=12x2+12x8 22x=\frac{1}{2}x^2+\frac{1}{2}x8

22x=12x2+4x 22x=\frac{1}{2}x^2+4x

0=12x2+4x22x 0=\frac{1}{2}x^2+4x-22x

0=12x218x 0=\frac{1}{2}x^2-18x

0=12x(x36) 0=\frac{1}{2}x(x-36)

For the equation to be balanced, x x needs to be equal to 36.

Answer

x=36 x=36