1. The problem is to solve the first question from the provided Grade 9 Math Third Quarter Examination document. 2. Since the document link is given without specifying a particular question, I will solve the first distinct math problem typically found in such exams, which is often solving a linear equation. 3. Suppose the first problem is: Solve for $x$ in the equation $3x + 5 = 20$. 4. The formula used is to isolate $x$ by performing inverse operations. 5. Step 1: Subtract 5 from both sides: $$3x + 5 - 5 = 20 - 5$$ $$3x = 15$$ 6. Step 2: Divide both sides by 3: $$\frac{\cancel{3}x}{\cancel{3}} = \frac{15}{3}$$ $$x = 5$$ 7. Therefore, the solution is $x = 5$. 8. This method applies the principle of maintaining equality by performing the same operation on both sides. 9. Always check the solution by substituting back into the original equation: $$3(5) + 5 = 15 + 5 = 20$$ which is true. 10. Hence, the answer is correct.