Verified Answer :

The answer will be A. -1+=\(\sqrt{21}\)/2

Answer:

A quadratic equation \(ax^2+bx+c = 0\)    ....[1] where, a, b and c are coefficient.

Then the solution is given by:

\(x = -\frac{b \pm \sqrt{b^2-4ac}}{2a}\)        ....[2]

As per the statement:

Given the equation:

\(x^2=5-x\)

⇒\(x^2+x-5 = 0\)

On comparing with [1] we have;

a =1, b = 1 and c = -5

Then substitute these in [2] we have;

\(x = \frac{-1 \pm \sqrt{1^2-4(1)(-5)}}{2(1)} =\frac{-1 \pm \sqrt{1+20}}{2} =\frac{-1 \pm \sqrt{21}}{2}\)

Therefore, the values of x are:

\(x = \frac{-1 + \sqrt{21}}{2}\) , \(\frac{-1 - \sqrt{21}}{2}\)