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 - 3)(y + 4)
(y x y) + (y x 4) + (-3 x y) + (-3 x 4)
y² + 4y - 3y - 12
y² + y - 12

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(8 + 9)(2)
a = ½(17)(2)
a = ½(34) = \( \frac{34}{2} \)
a = 17

The formula for area is πr². Radius is circle \( \frac{diameter}{2} \):

r = \( \frac{d}{2} \)
r = \( \frac{4}{2} \)
r = 2
a = πr²
a = π(2²)
a = 4π

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 -48 as well and sum (Inside, Outside) to equal -2. For this problem, those two numbers are -8 and 6. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - 2y - 48
y² + (-8 + 6)y + (-8 x 6)
(y - 8)(y + 6)

An acute angle measures less than 90°, a right angle measures 90°, and an obtuse angle measures more than 90°.