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.

2a⁹ - 5a⁹ = -3a⁹

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 equal sign and the answer on the other.

8z - 4 = 3 - 4z
8z = 3 - 4z + 4
8z + 4z = 3 + 4
12z = 7
z = \( \frac{7}{12} \)
z = \(\frac{7}{12}\)

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

x² + 17x + 72 = 0
(x + 8)(x + 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x + 8) or (x + 9) must equal zero:

If (x + 8) = 0, x must equal -8
If (x + 9) = 0, x must equal -9

So the solution is that x = -8 or -9

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 entire length of this line is represented by AD which is AB + BD:

AD = AB + BD