Look at the following rectangle:
The area of the rectangle is 7.
What is the perimeter of the rectangle?
To solve this problem, we'll need to find the value of X and then use this value to find the perimeter of the rectangle. Follow these detailed steps:
- Step 1: Set up the equation for the area.
Given the area of the rectangle is 7, and the sides are (X+5) and (X−1), the equation becomes:
(X+5)(X−1)=7
Expanding the left side, we have:
X2+5X−X−5=7
X2+4X−5=7
- Step 2: Simplify and solve the quadratic equation.
By moving all terms to one side, we have:
X2+4X−5−7=0
X2+4X−12=0
- Step 3: Factor the quadratic equation.
We factor the equation as:
(X+6)(X−2)=0
- Step 4: Solve for X using the zero-product property.
The solutions for X are:
X+6=0⇒X=−6
X−2=0⇒X=2
- Step 5: Use the positive X value to find the perimeter.
Since dimensions cannot be negative, X=2. Thus, the rectangle’s dimensions become:
Length=X+5=2+5=7
Width=X−1=2−1=1
- Step 6: Calculate the perimeter using the dimensions.
P=2×(Length+Width)=2×(7+1)=2×8=16
Therefore, the perimeter of the rectangle is 16.