Question

if 3 is solution of quadratic equations xpower2+4x-21 and find the other root​

Answer 1

If we compare the given equation with the standard quadratic equation i.e, ax²+bx+c=0, we get a=1, b=4, c= -21

Sum of the roots is given as,

$\alpha + \beta = - \frac{b}{a } \\ 3 + \beta = - \frac{4}{1} \\ \beta = - 4 - 3 \\ \beta = - 7$

Hence, the second root is -7.