Solve `x^(2)+x-2=0`

Explanation

For quadratic equation
` ax^(2)+bx +c=0`
`x=(-b+-sqrt(b^(2)-4ac))/(2a)`
So, for given equation ` x^(2)+x-2=0`
`x=(-1+-sqrt(1+8))/(2)=(-1+-3)/(2)=1,-2`