x2-4x+3=0
(x-3)(x-1)
x2-9x+14=0
x=2,7
x2+2x=15
x=-5,3
x2+3x+2=0
(x+1)(x+2)
x2+5x-24=0
x=-8,3
x2+11x+34=4
x=-6,-5
x2+3x-10=0
(x+5)(x-2)
x2+x-42=0
x=-7,6
x2+5x+6=20
x=-7,2