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 7a + 3a = 8a - 4y - 9 for a in terms of y.
| -15y + 3 | |
| 7y + 9 | |
| -\(\frac{1}{3}\)y - 2\(\frac{1}{3}\) | |
| -15y + 6 |