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.

5a + 4a = 9a

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

The volume of a cube is height x length x width:

v = h x l x w
v = 6 x 3 x 2
v = 36

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

The area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 3 x 6
a = 18