Algebra practice question

Answer: A. x ≤ 7

Subtract 2x: 2x − 9 ≤ 5. Add 9: 2x ≤ 14, so x ≤ 7. Because we divided by a positive number, the inequality sign stays the same.

Why the other answers are wrong

B. x ≥ 7

You solved correctly to get 7, but flipped the inequality sign — that only happens when you multiply or divide by a negative, and here you divided by positive 2.

C. x ≤ 2

The 2 here is the coefficient left after combining like terms (2x ≤ 14), not the solution; you still need to divide 14 by 2 to get x ≤ 7.

D. x ≥ 2

You stopped at the coefficient 2 from 2x ≤ 14 instead of dividing to get 7, and also reversed the inequality sign even though you divided by a positive number.

More Algebra questions

• Medium
  A system: 2x + y = 11 and x − y = 1. What is the value of x + y?
• Medium
  A phone's battery percentage is modeled by P = 100 − 8t, where t is the number of hours since it was unplugged…
• Medium
  If y = 2x − 1 and 3x + y = 14, what is the value of x?
• Medium
  If |2x − 3| = 7, what is the sum of all possible values of x?
• Medium
  Line k has equation y = (2/3)x + 1. Which equation represents a line perpendicular to line k?
• Medium
  At a bakery, 2 muffins and 3 cookies cost $13, while 4 muffins and 1 cookie cost $16. What is the cost, in dol…