X^2-(1/2+1/3)x+1/2*1/3=0
x^2-5/6 x+ 1/6=0
<span>х</span>²<span>=2х+8
х</span>²-2х-8=0
<span>D=b</span>²-4ac=2²-4*1*(-8)=4+32=36
<span>x1=-b+</span>√D/2a=2+6/2=8/2=4
<span>x2=-b-</span>√D/2a=2-6/2=-4/2=-2
<span>Ответ: х1=-2, х2=4
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(a-a²)²-a²(a-2)(a+2)+2a(7+3a²)=(a-a²)²-a²(a²-4)+2a(7+3a²<span>)=
=a</span>²-2a³+a⁴-a⁴+4a²+14a+6a³=4a³+5a²+14a=a(4a²+5a+14)
S6 = (a1 + a6)·6/2 = (а1 + а1 + 5d)·3 = (2a1 +5d)·3
d=-1 1/3 - (-3 2/3) = -1 1/3 + 3 2/3 = 2 1/3 = 7/3
S6 = (2·(-3 2/3) + 5·7/3)·3 =(-22/3 + 35/3)·3 = 13/3·3 = 13