Solve the linear equation: $3 x - 7 = 2 x + 5$

easy 1 mark Class 7 · Mathematics · Simple Equations

Answer

x=12

The correct answer is x=12 — Verify by substitution: $3 (12) - 7 = 36 - 7 = 29$ and $2 (12) + 5 = 24 + 5 = 29$ , which are equal.

Step-by-step solution

Subtract $2 x$ from both sides to obtain $x - 7 = 5$ because we want all $x$ terms on one side.
Add 7 to both sides to isolate $x$ , giving $x = 12$ .
Verify by substitution: $3 (12) - 7 = 36 - 7 = 29$ and $2 (12) + 5 = 24 + 5 = 29$ , which are equal.

Common mistake: Changing the sign of a term incorrectly when moving it to the other side

Concept tested: Solving linear equations