Your multiplying by -4 each time
-1x-4=4
4x-4=-16
-16x-4=64
Answer:

Step-by-step explanation:
You can use the work they gave you and continue from there:

First, simplify the numerator:

Finally, simplify the denominator:

Not sure what the question is but 3x + 7 is the algebraic expression that would represent this statement.
No, it will not be able to make a right triangle.
<em><u>Solution:</u></em>
Given that,
Joel wants to fence off a triangular portion of his yard for his chickens.
The length of three peices of fencing are 8 feet , 15 feet and 20 feet
For making it a right triangle it must satisfy the "Pythagorus theorem"
Pythagorean theorem, states that the square of the length of the hypotenuse is equal to the sum of squares of the lengths of other two sides of the right-angled triangle.
For a right angled triangle with sides a, b, c

Given sides are:
a = 8 feet
b = 15 feet
c = 20 feet
Substituting the values in above formula

Since the pythogoras formula is not satisfied, the given sides cannot form a right angled triangle
Thus , No, it will not be able to make a right triangle.