How do I solve the equation 3x + 7 = 22 step by step?

The goal is to get x alone on one side. Start with 3x + 7 = 22. First move the +7 to the right side; when a term crosses the equals sign its sign changes, so +7 becomes −7. That gives 3x = 22 − 7, which is 3x = 15. Now x is multiplied by 3, so to undo that, divide both sides by 3: x = 15 ÷ 3 = 5. So x = 5. Always verify by substituting back into the original equation: 3 × 5 + 7 = 15 + 7 = 22, which matches the right side, so the answer is correct. This checking step is worth doing in exams to catch mistakes.