We can always check our work in algebra by substituting our answer back into the original equation. Replacing x with 5, we calculate 2 × 5 = 10, and 10 + 5 = 15. Since the left side matches the right side, our solution is definitely correct.

We can always check our work in algebra by substituting our answer back into the original equation. Replacing x with 5, we calculate 2 × 5 = 10, and 10 + 5 = 15. Since the left side matches the right side, our solution is definitely correct.

I'm in Class 9. Teach me algebra like a patient teacher. Explain every calculation in very simple words, go slowly, and don't skip steps. Let me interrupt whenever I don't understand.”

Answer: In algebra, an equation is balanced like a scale. By applying inverse operations to both sides of $2x + 5 = 15$ , we find that $x = 5$ .

Step-by-step solution

Step 1: Understand What an Algebraic Expression Represents

In algebra, we use a letter like $x$ to stand for an unknown number that we want to discover. The expression $2x$ simply means $2$ multiplied by that mystery number $x$ . Adding $5$ means we take that doubled number and add $5$ , arriving at a total of $15$ .

Step 2: Isolate the Variable Term by Subtracting 5

To discover what $x$ is, our goal is to isolate $x$ by itself on the left side of the equals sign. We reverse the $+5$ by subtracting $5$ from both sides so the equation stays balanced. This leaves us with $2x = 10$ .

Step 3: Solve for x by Dividing by 2

Now we have $2$ times $x$ equals $10$ . To undo multiplication by $2$ , we divide both sides by $2$ . Dividing $10$ by $2$ gives $5$ , which reveals the value of our mystery number.

Step 4: Check Your Solution

We can always check our work in algebra by substituting our answer back into the original equation. Replacing $x$ with $5$ , we calculate $2 \times 5 = 10$ , and $10 + 5 = 15$ . Since the left side matches the right side, our solution is definitely correct.

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