Multiple choice

Roots of quadratic equation $5x^2\,-\,22x\,-\,15\,=\,0$ are

  1. $\displaystyle-\,5, \,\frac{-3}{5}$
  2. $\displaystyle\,5, \,\frac{3}{5}$
  3. $\displaystyle\,5, \,\frac{-3}{5}$
  4. None of these

Reveal answer Fill a bubble to check yourself
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.