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

y² + 2y - 8 = 0
(y - 2)(y + 4) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y - 2) or (y + 4) must equal zero:

If (y - 2) = 0, y must equal 2
If (y + 4) = 0, y must equal -4

So the solution is that y = 2 or -4

A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(3a)(6ab) - (5a²)(4b)
(3 x 6)(a x a x b) - (5 x 4)(a² x b)
(18)(a¹⁺¹ x b) - (20)(a²b)
18a²b - 20a²b
-2a²b

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

The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 36° - 66° = 78°