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.)
Solve -3a - 9a = -5a + 8z - 9 for a in terms of z.
| -13z + 5 | |
| 9z - 2 | |
| -5\(\frac{1}{2}\)z + 2 | |
| 8\(\frac{1}{2}\)z - 4\(\frac{1}{2}\) |