A monomial contains one term, a binomial contains two terms, and a polynomial contains more than two terms.

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(3 + 3)(3)
a = ½(6)(3)
a = ½(18) = \( \frac{18}{2} \)
a = 9

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

7a⁴ - 4a⁴ = 3a⁴

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 -20 as well and sum (Inside, Outside) to equal 1. For this problem, those two numbers are -4 and 5. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + y - 20
y² + (-4 + 5)y + (-4 x 5)
(y - 4)(y + 5)

Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).