1)
(х-2)^2=2-х
х^2-4х+4-2+х=0
х^2-3х+2=0
д=9-4×2×1=1
х1=(3-1)/2=1
х2=(3+1)/2=2
2)
х^2+х-12=-3х
х^2+х-12+3х=0
х^2+4х-12=0
д=16-4×1×(-12)=64
х1=(-4-8)/2=-6
х2=(-4+8)/2=2
3)
х+3-2!/(х+3)(7-х) +7-х=4
10-2!/(7х-х^2+21-3х)=4
5-!/(-х^2+4х+21)=2
!/(-х^2+4х+21)=3
-х^2+4х+21=9
-х^2+4х+21-9=0
-х^2+4х+12=0
х^2-4х-12=0
д=16-4×(-12)×1=64
х1=(4-8)/2=-2
х2=(4+8)/2=6