Question

СРОЧНО ПЛИЗ!! Решите уравнение: 1) log4_x=1/2; 3)log1/3(5x-21)=-2
2)lgx=2; 4)lg(3-x)=-1

Answer 1

log4_x=1/2; х= 4∧1/2; х=2. 3)log1/3(5x-21)=-2(5х-21) = (1/3) ∧-2;  5х - 21 = 9; 5х = 30; х = 6.
2)lgx=2; х = 10∧2; х = 100.
 4)lg(3-x)=-1; 3 - х = 10 ∧-1; 3 - х = 0,1; х = 3 - 0,1; х = 2,9.