Question

log(7) 9+log(7) 2401-log (7) 73

Answer 1

$1)log_7 9 +log_7 7^4 -log_7 63=log_79 -log_7 63 +4log_7 7= \ \ =log_7 frac{9}{63} +4*1=log_7 frac{1}{7} +4=log_7 7^{-1} +4= \ \ =-1*log_7 7 +4=-1*1+4=3 \ \ \ 2) left { {{4x+y=3} atop {3x-2y=5}} right. left { {{y=3-4x} atop {3x-2(3-4x)=5}} right. \ 3x-6+8x=5 \ 11x=11 \ x=1 \ \ y=3-4x=3-4*1=-1 \ OTBET: (1;-1) \ \ frac{5(x+y)}{x-y} = frac{5(1-1)}{1+1} =0 \ \ OTBET: 0$