Question

If the roots of the equation 12x² + mx + 5 = 0 are in the ratio 3 : 2 then m is equal to

• A. 12/5
• B. 5/12
• C. $5\sqrt{10}$/12
• D. $5\sqrt{10}$

Answer 1

Answer: (D)

$5\sqrt{10}$

Answer 2

Let roots are 3a and 2a

then 5a = – $\frac{m}{12}$ Ž a = $\frac{- m}{60}$ and 6a² = $\frac{5}{12}$

on putting the value of a in it

6 ×$\frac{m^{2}}{3600}$=$\frac{5}{12}$Ž 6 ×$\frac{m^{2}}{3600}$=$\frac{5}{12}$

Ž m² = 250 Ž 5$5\sqrt{10}$