CMA Foundation · Fundamentals of Business Mathematics and Statistics · Quadratic Equations
Using the quadratic formula, what are the roots of 3x^2 - 5x - 2 = 0?
The roots are 2 and -1/3. The discriminant is 25+24=49 with square root 7, so x equals (5+7)/6 which is 2, or (5-7)/6 which is -1/3.
- Ax = 2 and x = -1/3Correct
- Bx = -2 and x = 1/3
- Cx = 2 and x = 1/3
- Dx = 5 and x = -2
Explanation
Discriminant = 25 + 24 = 49, square root 7. x = (5 ± 7)/6 gives 12/6 = 2 and -2/6 = -1/3. Option with 1/3 results from ignoring the sign of c in the discriminant or the root.
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