3x^3+x^2+3x+1=3x(x^2+1)+(x^2+1)=(x^2+1)((3x+1)
1)
Д=12^2-4*1*36=144-144=0
x1= 12/2=6
2)
D= -30^2-4*25*9=900-900=0
x1= 30/50=0.6
-3x^2 - 7x + 6 = 0 | * (-1)
3x^2 - 7x - 6 = 0
D = 49 + 4*3*6 =121 = 11
7 + 11/ 6 = 3
7 - 11/6 = 0.6
X+y=1
4x+2y=6
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x+y=1
2x+y=3
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(2x+y)-(x+y)=3-1
2x-x+y-y=2
x=2
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y=1-x, y=1-2, y=-1
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/x,y/=/2,-1/
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