[tex]x^2-4x+1=0\\
x^2-4x+4-3=0\\
(x-2)^2=3\\
|x-2|=\sqrt3\\
x-2=\sqrt3 \vee x-2=-\sqrt3\\
x=2+\sqrt3 \vee x=2-\sqrt3[/tex]
[tex]x^2+6x-9=0\\
x^2+6x+9-18=0\\
(x+3)^2=18\\
|x+3|=\sqrt{18}=3\sqrt2\\
x+3=3\sqrt2 \vee x+3=-3\sqrt2\\
x=-3+3\sqrt2 \vee x=-3-3\sqrt2\\[/tex]
[tex]x^2+20x+3=0\\
x^2+20x+100-97=0\\
(x+10)^2=97\\
|x+10|=\sqrt{97}\\
x+10=\sqrt{97} \vee x+10=-\sqrt{97}\\
x=-10+\sqrt{97} \vee x=-10-\sqrt{97}[/tex]
[tex]x^2-2x-5=0\\
x^2-2x+1-6=0\\
(x-1)^2=6\\
|x-1|=\sqrt6\\
x-1=\sqrt6 \vee x-1=-\sqrt6\\
x=1+\sqrt6 \vee x=1-\sqrt6[/tex]
