Roots of quadratic equation $5x^2\,-\,22x\,-\,15\,=\,0$ are
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$\displaystyle-\,5, \,\frac{-3}{5}$
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$\displaystyle\,5, \,\frac{3}{5}$
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$\displaystyle\,5, \,\frac{-3}{5}$
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None of these
C
Correct answer
Explanation
5x^2 - 22x - 15 = 0. Using the quadratic formula: x = [22 +/- sqrt(484 - 4(5)(-15))] / 10 = [22 +/- sqrt(484 + 300)] / 10 = [22 +/- sqrt(784)] / 10 = [22 +/- 28] / 10. Roots are 50/10 = 5 and -6/10 = -3/5.