Solve for x: 7x - 4 = 3x + 20

Solve for x: 7x - 4 = 3x + 20

• A. 6
• B. 2
• C. 4
• D. 8

Answer: (A)

Solving linear equations by isolating the variable on one side is the idea here. You want to get all the x terms together and the constants on the other side, while keeping the equation balanced by doing the same operation to both sides. Start with 7x - 4 = 3x + 20. Subtract 3x from both sides to move the x term on the right to the left: 4x - 4 = 20. Then add 4 to both sides to move the constant term to the right: 4x = 24. Divide both sides by 4 to isolate x: x = 6. You can check by substitution: plug in x = 6, the left side is 7(6) - 4 = 42 - 4 = 38, and the right side is 3(6) + 20 = 18 + 20 = 38. Since both sides match, x = 6 is correct. Other numbers don’t balance the equation when substituted, so they aren’t solutions.

Solving linear equations by isolating the variable on one side is the idea here. You want to get all the x terms together and the constants on the other side, while keeping the equation balanced by doing the same operation to both sides.

Start with 7x - 4 = 3x + 20. Subtract 3x from both sides to move the x term on the right to the left: 4x - 4 = 20. Then add 4 to both sides to move the constant term to the right: 4x = 24. Divide both sides by 4 to isolate x: x = 6.

You can check by substitution: plug in x = 6, the left side is 7(6) - 4 = 42 - 4 = 38, and the right side is 3(6) + 20 = 18 + 20 = 38. Since both sides match, x = 6 is correct.

Other numbers don’t balance the equation when substituted, so they aren’t solutions.