x^2-4x+3=0

try plugging in 2 for x and you will see that it does not work:

(2^2)-(4*2)+3=0

4-8+3=0

-1=0 see?

I have attached a graph, where it is evident that the answers are

x = 1 and x = 3

It is difficult to see on the one I have attached but graph it yourself and trace the line and you will see. Remember always check your answers by plugging them back into the equation.