To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

-8b(b - y)
-8(1)(1 - 6)
-8(1)(-5)
(-8)(-5)
40

The area of a parallelogram is equal to its length x width:

a = l x w
a = a x b
a = 8 x 9
a = 72

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(6 + 6)(3)
a = ½(12)(3)
a = ½(36) = \( \frac{36}{2} \)
a = 18

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 28 as well and sum (Inside, Outside) to equal 11. For this problem, those two numbers are 4 and 7. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 11y + 28
y² + (4 + 7)y + (4 x 7)
(y + 4)(y + 7)

The area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 1 x 7
a = 7