Question

x×(x-4)+3=0
(x-3)×(x+3)=0
x²-2x+1=0

Answer 1

$a).x(x-4)+3=0 \\ x^2-4x+3=0 \\ (x-1)(x-3)=0 \\ x-1=0 \\ x=0+1 \\ x=1 \\ x-3=0 \\ x=0+3 \\ x=3 \\ S=\{2;3\}$
$b).(x-3)(x+3)=0 \\ x-3=0 \\ x=0+3 \\ x=3 \\ x+3=0 \\ x=0-3 \\ x=-3 \\ S=\{-3;3\}$
$c).x^2-2x+1=0 \\ (x-1)^2=0 \\ x-1=0 \\ x=0+1 \\ x=1$