1)0,3^√7^(-x)=0,3^(1/343) √ -12-ой степени!
12
√7^(-x)=1/7^3
-x/12=-3; x=-3*(-12); x=36
2)log(2) (1+3log(2) x)=2
log(2) (1 + log(2) x^3)=log(2) 4
1+log(2) x^3=4
log(2) x^3=3; x^3=2^3; x=2
3)2lg^2 x + 2log^2(5) 0,2= 1,5+1,5lgx;
2lg^2 x -1,5lgx + 2*(log(5) 1/5)^2-1,5=0 2(log(5) (1/5))^2=2*(-1)^2=2
2lg^2 x-1,5lgx + 2*(-1)^2-1,5=0
t=lgx; 2t^2-1,5t+0,5=0; D=2,25-4*2*0,5=2,25-4=?