Answer:
A. 6 feet
B. 38 feet of fencing total
Explanation:
a. We are given 78 square feet as the total area that the fence encloses. Given this, we can use the A=l*w to solve for the side lengths.
A=l*w
Plug in known variables and simplify...
Step 1: Subtract 78 from both sides.
x^2+7x−78=78−78
x^2+7x−78=0
Step 2: Factor left side of equation.
(x−6)(x+13)=0
Step 3: Set factors equal to 0.
x−6=0 or x+13=0
x=6 or x=−13
For this case we will need to use the positive value.
so to check the answer, we can plug in 6 for x and check if it will equal 78.
(6+7)(6)
13*6
78
b. now given the value of x, we need to solve for the total amount of fencing by finding the perimeter.
We already know that one side is 6+7 or 13, and the other side is 6, so to find perimeter we use the formula 2l+2w
and solve...
2*13+2*6
26+12
38