Question

If the equation $3x^2+bx+8=0$ has roots $1$ and $\frac{8}{3}$, then what is the value of $b$?

• A. $-11$
• B. $5$
• C. $11$
• D. $-5$

Answer 1

The correct option is A $-11$

Given equation is $3x^2+bx+8=0$
The roots are $1$ and $\frac{8}{3}$
In a quadratic equation $a{x}^2+bx+c=0$ if the roots are $1$ and $\frac{c}{a}$
then the sum of coefficients must be zero.
$\Rightarrow a+b+c=0$
So here,
$3+b+8=0$
$\Rightarrow b=-11$