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 + 7a = 3a + 3z + 9 for a in terms of z.
| -4z + 9 | |
| -1\(\frac{1}{7}\)z + \(\frac{1}{7}\) | |
| \(\frac{5}{18}\)z + \(\frac{7}{18}\) | |
| \(\frac{1}{13}\)z - \(\frac{3}{13}\) |