To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses:

(y - 8)(y + 3)
(y x y) + (y x 3) + (-8 x y) + (-8 x 3)
y² + 3y - 8y - 24
y² - 5y - 24

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 1 + 4 + 9 + 1
p = 15

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

z² + 3z - 4 = 5z - 1
z² + 3z - 4 + 1 = 5z
z² + 3z - 5z - 3 = 0
z² - 2z - 3 = 0

Next, factor the quadratic equation:

z² - 2z - 3 = 0
(z + 1)(z - 3) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z + 1) or (z - 3) must equal zero:

If (z + 1) = 0, z must equal -1
If (z - 3) = 0, z must equal 3

So the solution is that z = -1 or 3

The formula for circumference is circle diameter x π:

c = πd
c = 8π

To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce 63 as well and sum (Inside, Outside) to equal -16. For this problem, those two numbers are -9 and -7. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 16y + 63
y² + (-9 - 7)y + (-9 x -7)
(y - 9)(y - 7)