Which of the following quadratic equations has \(-\frac{1}{2}\) and \(\frac{3}{4}\) as its roots?
A. 8x2 + 11x - 3 = 0 B. 8x2 -11x – 3 = 0 C. 8x2 + 2x -3 = 0 D. 8x2 - 2x – 3 = 0
Correct Answer: D
Explanation
X2 - (sum of the roots)x + (product of the roots) = 0 Sum of the roots \(= -\frac{1}{2}+\frac{3}{4} = \frac{-2+3}{2}=\frac{1}{4}\) Product of the roots = \(-\frac{1}{2}\times \frac{3}{4}=\frac{-3}{8}\\ X^2-\left(\frac{1}{4}\right)x-\frac{3}{8} = 0. Taking \hspace{1mm}the\hspace{1mm} common\) \(8x^2-2x-3=0\);