Question

Question 1 (iv)

Find the roots of the quadratic equations by using the quadratic formula in the following question.

$-x^2+7x-10=0$

Answer 1

Given equation is $-x^2+7x-10=0$
on comparing with $a{x}^2$ + bx + c = 0, we get
a = - 1, b = 7 and c = - 10
by quadratic formula, $x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$
$=\frac{-\left(7\right)\pm \sqrt{(7{)}^2-4(-1\left)\right(-10)}}{2(-1)}=\frac{7\pm \sqrt{49-40}}{-2}$
$=\frac{-7\pm \sqrt{9}}{-1}=\frac{-7\pm 3}{-2}=\frac{-4}{-2},\frac{-10}{-2}=2,5$
So, 2 and 5 are two roots of the given equation.