2.6 7^((2x^2-5x-9)/2)=(√2 ^3log(2) 7
7^((2x^2-5x-9)/2) =2^log(2) (7^ 3/2)
7^((2x^2-5x-9)/2)=7^(3/2)
(2x^2 -5x -9)/2=3/2
2x^2-5x-9=3; 2x^2-5x-12=0; D=25-4*2*(-12)=25+96=121=11^2;
x1=(5-11)/4=-6/4=-3/2; x2=4
Ответ. -1,5; 4
2.8 5*(5^ (-2))^sin^2 x+ 4* 5^cos2x =5^2)^(1/2 sin2x;
5^(1-2sin^2 (x) +4*5^cos(2x) =5^sin(2x);
5^(1-1+cos(2x) +4*5^cos(2x) =5^sin(2x)
5*5^cos(2x)=5^sin(2x)
5^cos(2x) =5^sin(2x); cos(2x)=sin2x; cos(2x)-sin(2x)=0; -tg(2x)=-1
tg(2x)=1; 2x=π/4+πn
x=π/8+π/2 *n
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2.12 2^(3(x-3)/(3x-7)) * ∛√(1/4)^(3x-1)/(x-1)=1 6
2^(3(x-3)/(3x-7)) * (2^-2)^((3x-1)/(6(x-1))=1; ∛√a=√a=a^(1/6)
2^(3(x-3)/(3x-7)) *2^(-2*(3x-1 /(6(x-1))=1; 2^0=1
(3x-9)/(3x-7)+((1-3x)/(3x-3)=0
((3x-9)*(3x-3) +(1-3x) *(3x-7) ) /((3x-7)(3x-3)=0
9x^2 -9x-27x+27 +3x-7-9x^2 +21x)=0; (3x-7)(3x-3)≠0
-12x+20=0; x=20/12; x=5/3