Simplify the expression: \( x^2-2x-4=0\). Use the quadratic formula to get
\(\frac{2 \pm \sqrt{(-2)^2-4\cdot1\cdot(-4)}}{2}\)
\(\frac{2 \pm \sqrt{4-(-16)}}{2}\)
\(\frac{2 \pm \sqrt{20}}{2}\)
\(1 \pm \sqrt{5} = r\)
So r is irrational, so this cannot be done.
