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