JAMB 2013 Mathematics · Question 17
Evaluate 3(x + 2) > 6(x + 3)
Options
- A.x < 4
- B.x > -4
- C.x < -4
- D.x > 4
Answer: C. x < -4
Explanation written with AI and checked against the answer key
Analysis
We are asked to solve a linear inequality. The goal is to isolate the variable on one side of the inequality sign to determine its range of values.
Concept
When solving inequalities, the rules are very similar to solving equations, with one critical exception: if you multiply or divide both sides by a negative number, you must reverse the inequality sign.
Step-by-Step Solution
Step 1: Expand the brackets Distribute the numbers outside the parentheses:
Step 2: Group the like terms Move the terms to one side and the constant numbers to the other. Let's move to the right and to the left:
Step 3: Simplify both sides
Step 4: Solve for Divide both sides by :
This can also be written as:
Conclusion
By simplifying the inequality, we found that must be less than . This matches option C.
Exam Tip
When you have an inequality like , it is exactly the same as . If you ever feel confused about which way the sign should face, read it out loud: " is greater than " is the same as saying " is less than ." Always double-check your sign direction after dividing by a negative number!
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