Question

Solve using formula method : $7p^2-5p=2$

Answer 1

Given , $7p^2-5p-2=0$

Here a $=$ 7 , b $=$ -5 , c $=$ -2

For quadratic equation , roots are :

$x=\frac{-b+\sqrt{b^2-4ac}}{2a}$

$P=\frac{-(-5)+\sqrt{25-4\times 7\times -2}}{2\times 7}$

$=\frac{5\pm \sqrt{25+28\times 2}}{14}$

$=\frac{5\pm \sqrt{25+56}}{14}$

$=\frac{5\pm \sqrt{81}}{14}$

$=\frac{5+9}{14}$

$\therefore p=\frac{14}{14}=1$

or

$\therefore p=\frac{-4}{14}$

$=\frac{-2}{7}$