Answer
The provided statement does not make sense.
Work Step by Step
Consider the quadratic equation of the form \[a{{x}^{2}}+bx+c=0\].
So, the solution of quadratic equation is given by the formula:
\[x=\frac{-b\pm \sqrt{{{b}^{2}}-4ac}}{2a}\]
So, for quadratic equation ${{x}^{2}}-x-2=0$ the value of \[a,b\] and \[c\]is:
$\begin{align}
& a=1 \\
& b=-1 \\
& c=-2
\end{align}$
So, solution is:
$\begin{align}
& x=\frac{-\left( -1 \right)\pm \sqrt{{{\left( -1 \right)}^{2}}-4\times 1\times \left( -2 \right)}}{2\times 1} \\
& =\frac{+1+\sqrt{9}}{2},\frac{+1-\sqrt{9}}{2} \\
& =2,-1
\end{align}$
By factorization method, the above quadratic equation can be solved as:
$\begin{align}
& {{x}^{2}}-x-2=0 \\
& {{x}^{2}}-2x+x-2=0 \\
& x\left( x-2 \right)+1\left( x-2 \right)=0 \\
& \left( x+1 \right)\left( x-2 \right)=0
\end{align}$
Further calculation shows that:
\[x=-1,2\]
The fastest way for me to solve ${{x}^{2}}-x-2=0$ is to use the factorization method.
