JAMB 2025 Mathematics · Question 20
Given that a * b = + (a - b). Find the value of 3 * 2
Options
- A.-6
- B.
- C.
- D.-1
Answer: B.
Explanation written with AI and checked against the answer key
1. Analyze the question
You are given a binary operation defined as . You need to substitute the values and into this formula to find the result.
2. Explain the concept
A binary operation is simply a rule that tells you how to combine two numbers to get a new result. In this case, the rule has two parts:
- A fraction part:
- A subtraction part:
To solve, we calculate each part separately and then add them together.
3. Show the solution
Step 1: Identify the values
Step 2: Substitute into the formula
Step 3: Solve the fraction part
Step 4: Solve the subtraction part
Step 5: Combine the results
To add these, convert to a fraction with a denominator of :
So,
4. Identify the answer
The calculated value is , which corresponds to option B.
5. Tip
When dealing with binary operations in JAMB, always use brackets to separate the different parts of the equation. This prevents "sign errors" (like accidentally subtracting when you should be adding) and keeps your work organized. If you get a fraction, always check if it can be simplified or if it needs to be converted to a mixed fraction to match the options provided.
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