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 - 5)(y + 2)
(y x y) + (y x 2) + (-5 x y) + (-5 x 2)
y² + 2y - 5y - 10
y² - 3y - 10

A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

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:

c² - 12c + 13 = -5c + 1
c² - 12c + 13 - 1 = -5c
c² - 12c + 5c + 12 = 0
c² - 7c + 12 = 0

Next, factor the quadratic equation:

c² - 7c + 12 = 0
(c - 3)(c - 4) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (c - 3) or (c - 4) must equal zero:

If (c - 3) = 0, c must equal 3
If (c - 4) = 0, c must equal 4

So the solution is that c = 3 or 4

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