Solve the linear equation for x: 7x - 15 = 3x + 21.
Answer and explanation
Correct answer: B. x = 9
- Step 1: Subtract 3x from both sides: 4x - 15 = 21. Step 2. Add 15 to both sides: 4x = 36. Step 3. Divide by 4: x = 9. Answer: x = 9. Why not the others: x = 6 adds 15 incorrectly; x = 12 divides 48. x = 4 does not fit.
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