Question

If 5x = 25, what is x?

• A. 3
• B. 4
• C. 5
• D. 6

Hint:

For simple equations, divide to isolate the variable and verify.

Answer 1

The Correct Option is C

Step-by-step Solution

1. Identify the structure of the equation.
   The equation is linear and has the form a × x = b with a = 5 and b = 25.
2. Choose the inverse operation to isolate x.
   x is being multiplied by 5, so use the inverse operation: divide by 5. (This is valid because 5 ≠ 0.)
3. Apply the Division Property of Equality to both sides.
   (5x) ÷ 5 = 25 ÷ 5
4. Simplify the left side.
   (5x) ÷ 5 = (5 ÷ 5) · x = 1 · x = x
5. Simplify the right side.
   25 ÷ 5 = 5
6. Conclude the value of x.
   Therefore, x = 5.
7. Verification (substitution check).
   Substitute x = 5 back into the original equation:
   5 × 5 = 25 ✓ (true). Hence, the solution is correct.

Alternate quick method

1. Think: “What number times 5 equals 25?”
2. Since 25 ÷ 5 = 5, immediately x = 5.
3. This matches the algebraic result.

Common mistakes to avoid

• Dividing only one side by 5 (must divide both sides to keep equality balanced).
• Using subtraction instead of division (the inverse of multiplication is division).

Final Answer

x = 5 — this is the correct option.