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 -5a + 4a = -4a + 5z - 9 for a in terms of z.
| -z + 9 | |
| -\(\frac{7}{10}\)z + \(\frac{1}{5}\) | |
| \(\frac{6}{7}\)z + \(\frac{3}{7}\) | |
| \(\frac{3}{14}\)z - \(\frac{5}{14}\) |