Solve for x: 7x - 4 = 3x + 16.

Solve for x: 7x - 4 = 3x + 16.

• A. 4
• B. 6
• C. 5
• D. 7

Answer: (C)

Solving a linear equation by isolating the variable uses inverse operations on both sides. Start with 7x - 4 = 3x + 16. Subtract 3x from both sides to bring the x terms together: 4x - 4 = 16. Then add 4 to both sides to move the constant: 4x = 20. Divide both sides by 4 to solve for x: x = 5. This value makes both sides equal, since 7(5) - 4 = 31 and 3(5) + 16 = 31. Any other number would not balance the equation.

Solving a linear equation by isolating the variable uses inverse operations on both sides. Start with 7x - 4 = 3x + 16. Subtract 3x from both sides to bring the x terms together: 4x - 4 = 16. Then add 4 to both sides to move the constant: 4x = 20. Divide both sides by 4 to solve for x: x = 5. This value makes both sides equal, since 7(5) - 4 = 31 and 3(5) + 16 = 31. Any other number would not balance the equation.