y=1-9/x2 , х2 - х в квадрате.
(3-x)²+3x(x-4)=9-6x+x²+3x²-12x=4x²-18x+9
ответ: 2)
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T^2 - 7t + 2t - 14 = t^2 - 5t - 14 = (-10)^2 + 50 - 14 = 100 + 50 - 14 = 136.
6-6sin²x+5sinx-2=0
sinx=a
6a²-5a-4=0
D=25+96=121
a1=(5-11)/12=-1/2
sinx=-1/2
1)x=-π/6+2πn,n∈z
-5π/2≤-π/6+2πn≤-π
-15≤-1+12n≤-6
-14≤12n≤-5
-7/6≤n≤-5/12
n=-1⇒x=-π/6-2π=-13π/6
2)sinx=7π/6+2πk,k∈z
-5π/2≤7π/6+2πk≤-π
-15≤7+12k≤-6
-22≤12k≤-13
-11/6≤k≤-13/12
нет решения
a2=(5+11)/12=4/3
sinx=1 1/3>1
нет решения