Algebra practice question

Answer: 4.4 or 22/5

Multiply everything by 12: 4(2x − 1) − 3(x + 2) = 12, so 8x − 4 − 3x − 6 = 12, 5x − 10 = 12, 5x = 22, x = 22/5 = 4.4.

Common wrong answers

If you answered 2

2 comes from 8x − 4 − 3x + 6 = 12 (not distributing the minus onto the +2), giving 5x = 10.

If you answered 12

12 is the right side after multiplying by 12, not x.

If you answered 3.4

3.4 comes from 5x = 17, mis-adding the constants; −4 − 6 = −10, so 5x = 22.

More Algebra questions

• Very hard
  For what value of c does the system 3x − 2y = 8 and 9x + cy = 5 have no solution?
• Very hard
  In the system 5x + 4y = 32 and 3x − 2y = 6, what is the value of 8x + 2y?
• Very hard
  The solution set of the inequality |ax − b| ≤ 6, where a and b are constants and a > 0, is 3 ≤ x ≤ 9. What is …
• Very hard
  The function f is linear, and for every value of x, f(x + 2) − f(x) = 6. If f(5) = 4, what is the value of f(0…
• Very hard
  In the system of equations 2x + 3y = 12 and 5x − 2y = k, where k is a constant, the solution (x, y) satisfies …
• Very hard
  In the xy-plane, the system of equations kx + 6y = 12 and 2x + (k − 1)y = 6, where k is a constant, has infini…