Sinxsin2x+cos(x+2x)=sinxsin2x+cosxcos2x-sinxsin2x=cosxcos2x=0
cosx=0⇒x=π/2+πn,n∈z
cos2x=0⇒2x=π/2+πk⇒x=⇒π/4+πk/2,k∈z
-2; -4; -8;...
q = -4:(-2) = 2
S₇ = b₁(q⁷-1)/(q -1)
S₇ = -2*(2⁷-1)/(2 -1) = -2*127 = -254
<em>Ответ: во вложении Объяснение:</em>
<em />
X+2-3x2-6x=0
-3x2-5x+2=0
D= 25-4*(-3)*2=25+24=49=7^2
x=5+7/-6=-2
x=5-7/-6=одна третья
9.
...........= -2,4х+3,6у-6-6х-9у+6,5= - 8,4х - 5,4у+0,5
10.
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