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 volume of a cube is height x length x width:

v = h x l x w
v = 9 x 8 x 4
v = 288

The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

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:

b² + 6b + 3 = b - 3
b² + 6b + 3 + 3 = b
b² + 6b - b + 6 = 0
b² + 5b + 6 = 0

Next, factor the quadratic equation:

b² + 5b + 6 = 0
(b + 2)(b + 3) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (b + 2) or (b + 3) must equal zero:

If (b + 2) = 0, b must equal -2
If (b + 3) = 0, b must equal -3

So the solution is that b = -2 or -3

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.

3a³ - 8a³ = -5a³