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(an) -8;-6,5;-5...
a1=-8, a2=-6,5
d=a2-a1=-6,5-(-8)=-6,6+8=1,5
a10=a1+9d=-8+8*1,5=-8+13,5=5,5
S10=(a1+a10)*10:2=(a1+a10)*5
S10=(-8+5,5)*5=-2,5*5=-12,5
Ответ: а10=5,5 S10=-12,5
{log(2,1)(x²+2x-10≥log(2,1)(x+2)
{|x|<7
1)
{x+2>0⇒x>-2
{x²+2x-10>0 D=4+40=42 x1<(-2-√42)/2 U x2>(-2+√42)/2
{x²+2x-10≥x+2⇒x²+x-12≥0 x1+x2=-1 U x1*x2=-12 x1≤-4 U x2≥3
x≥3
2)
-7<x<7
x∈[3;7)