Question

If $\alpha$ and $\beta$ are the roots of the equation $x^2+3x-4=0,$ then $\frac{1}{\alpha }+\frac{1}{\beta }$ is equal to

• A. $\frac{-3}{4}$
• B. $\frac{3}{4}$
• C. $\frac{-4}{3}$
• D. $\frac{3}{2}$

Answer 1

Answer: (B)

Since, $\alpha$ and $\beta$ are the roots of the equation
$x^2+3x-4=0$
Then,$\alpha +\beta =-3$ and $\alpha \beta =-4$
Now, $\frac{1}{\alpha }+\frac{1}{\beta }=\frac{\alpha +\beta }{\alpha \beta }=\frac{-3}{-4}=\frac{3}{4}$