Question

Can someone explain to me how to do this?

Answer 1

`Answer: \\ {x}^(2) + 1 = 5x\Leftrightarrow {x}^(2) - 5x + 1 = 0 \\ x = \frac{ - b \pm \sqrt{ {b}^(2) - 4ac } }{2a} = (5\pm √(25 - 4) )/(2) = (5 \pm √(21) )/(2) \\ \Rightarrow A \: \& \: C`