Question

Solve each equation. Check your solution.

$12=-7f-9$

Short answer

The solution of the given equation $f=-3$.

Step-by-step solution

Step 1. Isolate the variable.

$\begin{array}{l}12=-7f-9\\ -7f=12+9\end{array}$

Step 2. Solve the equation.

$\begin{array}{l}-7f=21\\ f=\frac{21}{-7}\\ f=-3\end{array}$

Step 3. Check the solution by putting the value of f into the given equation.

$\begin{array}{l}12=-7f-9\\ 12=-7(-3)-9\\ 12=21-9\\ 12=12\end{array}$

Hence proved.