Question

Physically what does it mean if the solution of quadratic equation are complex numbers?

Answer 1

so the roots are not real,
this means that the curve does not cut the x axis

Answer 2

is it it have no solution

Answer 3

complex solutions are solutions

Answer 4

for example
\[x^2+1=0\]
\[x=\frac{-0\pm\sqrt{0^2-4(1)(1)}}{2}\]\[x=\frac{\pm2i}2=\pm i\]

if we plot
\[y(x)=x^2+1=0\]