Solve for x: 2x + 7 = 19.

Solve for x: 2x + 7 = 19.

• A. 5
• B. 6
• C. 7
• D. 8

Answer: (B)

Solving a linear equation by isolating the variable means undoing the operations that surround x. Start with 2x + 7 = 19. Remove the added 7 by subtracting 7 from both sides, giving 2x = 12. Then divide both sides by 2 to isolate x, which yields x = 6. Substituting back confirms the result: 2(6) + 7 = 12 + 7 = 19, which matches the right-hand side. If you tried other values, they wouldn’t satisfy the equation: for example, x = 5 gives 2(5) + 7 = 17, x = 7 gives 21, and x = 8 gives 23, none of which equal 19.

Solving a linear equation by isolating the variable means undoing the operations that surround x. Start with 2x + 7 = 19. Remove the added 7 by subtracting 7 from both sides, giving 2x = 12. Then divide both sides by 2 to isolate x, which yields x = 6. Substituting back confirms the result: 2(6) + 7 = 12 + 7 = 19, which matches the right-hand side.

If you tried other values, they wouldn’t satisfy the equation: for example, x = 5 gives 2(5) + 7 = 17, x = 7 gives 21, and x = 8 gives 23, none of which equal 19.