CMA Foundation · Fundamentals of Business Mathematics and Statistics · Quadratic Equations
The roots of the equation x^2 - 7x + 12 = 0 are:
The roots are 3 and 4. Factorising x^2 - 7x + 12 gives (x - 3)(x - 4) = 0 because 3 and 4 add to 7 and multiply to 12. Setting each factor to zero gives x = 3 or x = 4.
- A-3 and -4
- B3 and 4Correct
- C2 and 6
- D1 and 12
Explanation
Find two numbers with sum 7 and product 12: 3 and 4. So x^2 - 7x + 12 = (x-3)(x-4) = 0, giving x = 3 or 4. Option 1 has the wrong signs (sum would be -7). Options 3 and 4 have the right product 12 only for 1 and 12 or 2 and 6, but sums 13 and 8, not 7.
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