Question

log2(x-5)+log2(x+2)=3

Answer 1

log((x-5)*(x+2))=log(8);

x-5>0; x>5

x+2>=0; x>-2;

 

(x-5)(x+2)=8;

x^2-3x-18=0;

D=81;

x1=6

x2=-3

 

Ответ x=6