Solve for x: 5x - 7 = 23.

• A. x = 5
• B. x = 6
• C. x = 7
• D. x = 8

Answer: (B)

Solving a linear equation by isolating the variable is the goal here. Start with 5x − 7 = 23. Undo the subtraction of 7 by adding 7 to both sides, giving 5x = 30. Then undo the multiplication by 5 by dividing both sides by 5, which yields x = 6. A quick check: 5(6) − 7 = 30 − 7 = 23, which matches the right side. So the value that satisfies the equation is 6.