1. The problem asks to solve question 13, but since the exact question is not provided, I will assume it is a typical algebra problem involving solving an equation. 2. Let's consider a common example: Solve for $x$ in the equation $$2x + 3 = 11$$. 3. The formula used here is to isolate $x$ by performing inverse operations. 4. Step 1: Subtract 3 from both sides: $$2x + 3 - 3 = 11 - 3$$ $$2x = 8$$ 5. Step 2: Divide both sides by 2: $$\frac{\cancel{2}x}{\cancel{2}} = \frac{8}{2}$$ $$x = 4$$ 6. Therefore, the solution is $x = 4$. This method applies to linear equations where the goal is to isolate the variable by performing inverse operations step-by-step.