Question

x^2-4x-1=0

Answer 1

-b +/- square root of b^2 -4ac

all divided by 2a

4 +- sq rt(16-4(1)(-1)) divided by 2

4 +- sq rt (16 +4) divided by 2

4+- sq rt(20) divided by 2

4+/- 2 sqrt 5 divided by 2

2+sqrt 5 or 2-sqrt 5 = x