X²+6x+4=0
х₁+х₂=-6 х₁= - 6-х₂
х₁*х₂=4
(-6 -х₂)*х₂=4
-6х²-х²₂-4=0
х²₂+6х₂+4=0
D=36-16=20 =2√5
x₁=(-6+2√5)/2=√5-3
x₂=(-6-2√5)/2=-3-√5
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x^2+106x+693=0
x₁+x₂=-106
x₁*x₂=693
D=11236-2772=8464 √D=92
x₁=(-106+92)/2=-7
x₂=(-106-92)/2 =-99