1. Вычислить: Log3 4 — log3 16+log3 4/9; 2. Вычислить:

1) Log3 4 — log3 16+log3 4/9=Log3 4/ 16+log3 4/9=Log3 (4/16)*(4/9)=Log3 1/9=Log3 (3) ^-2=-2 2) 2 log7 27 – log7 81-2 log7 21=log7 27^2/81-2 log7 21=log7 729/ 81- log7 21 ^2=log7 9- log7 21 ^2=log7 (9/ 441)=log7 (1/ 49)=log7 (7^-2)=-2 3) 2 log2 8+log2 15/4 – log2 15=log2 (8^2*(15/4) – log2 15=log2 (64*15) /4) – log2 15=log2 (16*15) – log2 15=log2 (16*15) /15)=log2 (16)=log2 (2^4)=4 4) log3 7*log4 81*log7 2=log4 81*log7 2*1/ log7 3=log4 3^4*(log7 2/ log7 3)=4*log4 3*log3 2=4*log3 2*(1/ log3 4)=4*log3 2*(1/ log3 2^2)=4*log3 2*(1/ 2 log3 2)=(4*log3 2) / (2 log3 2)=4/2=2 5) Lg3 (log3 25+log3 2-log3 5)=Lg3 (log3 (25*2) -log3 5)=Lg3 (log3 50/ 5)=Lg3*log3 10=log10 3*log3 10=log10 3/ log10 3=1