Question

x²-3x+2=0.
x²-4x+3=0.
x²-5x+4=0

Answer 1

$x^2-3x+2=0,\\(D=9-8=1,)\\x=\frac{3\pm1}{2},\\x_1=2,\\x_2=1.$

$x^2-4x+3=0,\\(D=16-12=4,)\\x=\frac{4\pm2}{2} ,\\x_1=3,\\x_2=1.$

$x^2-5x+4=0,\\(D=25-16=9,)\\x=\frac{5\pm3}{2},\\ x_1=4,\\x_2=1.$