1. The problem is not clearly stated, but since you mentioned "10th 1lesson," I will assume you want a basic algebra problem suitable for 10th grade level. 2. Let's solve a simple linear equation: Solve for $x$ in the equation $$3x + 5 = 20$$. 3. The formula used here is to isolate $x$ by performing inverse operations. 4. Step 1: Subtract 5 from both sides to get rid of the constant term on the left: $$3x + 5 - 5 = 20 - 5$$ which simplifies to $$3x = 15$$ 5. Step 2: Divide both sides by 3 to solve for $x$: $$\frac{3x}{\cancel{3}} = \frac{15}{\cancel{3}}$$ which simplifies to $$x = 5$$ 6. Therefore, the solution to the equation is $x = 5$. This means if you substitute $x=5$ back into the original equation, it holds true: $$3(5) + 5 = 15 + 5 = 20$$ Hence, the answer is correct.