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.

4a + 8a = 12a

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.

5a x 2b = (5 x 2) (a x b) = 10ab

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

z² + 7z + 6 = 0
(z + 1)(z + 6) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z + 1) or (z + 6) must equal zero:

If (z + 1) = 0, z must equal -1
If (z + 6) = 0, z must equal -6

So the solution is that z = -1 or -6

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

-5b - 2 < \( \frac{b}{8} \)
8 x (-5b - 2) < b
(8 x -5b) + (8 x -2) < b
-40b - 16 < b
-40b - 16 - b < 0
-40b - b < 16
-41b < 16
b < \( \frac{16}{-41} \)
b < -\(\frac{16}{41}\)

The formula for circumference is circle diameter x π:

c = πd
c = 3π