1. The problem is to solve a grade 9 math question. Since no specific question was provided, let's consider a common algebra problem: Solve for $x$ in the equation $2x + 3 = 11$. 2. The formula used here is to isolate $x$ by performing inverse operations. Important rules: addition and subtraction undo each other, multiplication and division undo each other. 3. Start by subtracting 3 from both sides: $$2x + 3 - 3 = 11 - 3$$ which simplifies to $$2x = 8$$ 4. Next, divide both sides by 2 to solve for $x$: $$\frac{\cancel{2}x}{\cancel{2}} = \frac{8}{2}$$ which simplifies to $$x = 4$$ 5. Therefore, the solution to the equation $2x + 3 = 11$ is $x = 4$. This method can be applied to similar linear equations to find the value of the unknown variable.