$\begin{array}{c}x=? \\ 4 x+12 \quad 80-x=\end{array}$

Step 1 ：The problem seems to be a system of two equations, but the second equation is missing a value on the right side. However, if we assume that the two expressions are equal to each other, we can solve for x. So, the equation becomes: \(4x + 12 = 80 - x\)

Step 2 ：To solve for x, we can first combine like terms by adding x to both sides of the equation and subtracting 12 from both sides of the equation. This will give us: \(5x = 68\)

Step 3 ：Then, we can solve for x by dividing both sides of the equation by 5. This gives us \(x = 13.6\)

Step 4 ：This means that if we substitute x with 13.6 in the equation, both sides of the equation should be equal. Let's check this.

Step 5 ：Both sides of the equation are equal when x is 13.6. Therefore, the solution to the equation is correct.

Step 6 ：Final Answer: \(x = \boxed{13.6}\)