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

y² + 10y + 9 = 0
(y + 1)(y + 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y + 1) or (y + 9) must equal zero:

If (y + 1) = 0, y must equal -1
If (y + 9) = 0, y must equal -9

So the solution is that y = -1 or -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.

3a⁸ - 4a⁸ = -1a⁸

A cube is a rectangular solid box with a height (h), length (l), and width (w). The volume is h x l x w and the surface area is 2lw x 2wh + 2lh.

When solving an equation with two variables, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

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)(4)
a = ½(6)(4)
a = ½(24) = \( \frac{24}{2} \)
a = 12