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 - 4)(y - 5)
(y x y) + (y x -5) + (-4 x y) + (-4 x -5)
y² - 5y - 4y + 20
y² - 9y + 20

The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

c² - 12c + 35 = 0
(c - 5)(c - 7) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (c - 5) or (c - 7) must equal zero:

If (c - 5) = 0, c must equal 5
If (c - 7) = 0, c must equal 7

So the solution is that c = 5 or 7

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 2 x 4 = \( \frac{8}{2} \) = 4

A triangle is a three-sided polygon. It has three interior angles that add up to 180° (a + b + c = 180°). An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite (d = b + c). The perimeter of a triangle is equal to the sum of the lengths of its three sides, the height of a triangle is equal to the length from the base to the opposite vertex (angle) and the area equals one-half triangle base x height: a = ½ base x height.

A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.