Example1. Find the roots of Quadratic Equation `x^2+10x-56=0` by the method of perfect square
Solution: `x^2+10x-56=0`
`=>x^2+10x-56 = 0`
Comparing the given equation with the standard quadratic equation `ax^2+bx+c=0,`
we get, `a=1, b=10, c=-56.`
`:. Delta=b^2-4ac`
`=(10)^2-4 (1) (-56)`
`=100+224`
`=324`
`:. sqrt(Delta)=sqrt(324)=18`
Now, `alpha=(-b+sqrt(Delta))/(2a)`
`=(-(10)+18)/(2*1)`
`=8/2`
`=4`
and, `beta=(-b-sqrt(Delta))/(2a)`
`=(-(10)-18)/(2*1)`
`=-28/2`
`=-14`
|