(х-16)*9=126
х-16=126:9
х-16=14
х=14+16
х=30
28*(х+5)=224
х+5=224:28
х+5=8
х=8-5
х=3
(х+76):7=15
х+75=15*7
х+75=105
х=105-75
х=30
248:6=41(о2) 6•41+2=248 659:9=73(2) 9•73+2=659 876:7=125(1) 7•125+1=876
835:4=208(3) 4•208+3=835
Перейдем к основанию 7
1/(1+2log(7)3 -1)*(1- log(7)3/(2+log(7)3)=
=(1-1-2log(7)3)/(1+2log(7)3)*(log(37)3+2-log(7)3)/(log(7)3+2)=
=-4log(7)3/[(1+2log(7)3)(log(7)3+2)]