А) 7/8-7/12=21/24-14/24=7/24
б) 3 2/7* 14=14*3+14*2/7=42+4=46
в) (3.7-1.4):3/7=(3.7-0.25)*7/3=(3.45*7)/3=24.15/3=8.05
Log3log8log2 (x-5) = log3(2) -1
log3log8log2 (x-5) = log3(2) - log3(3)
log3log8log2 (x-5) = log3(2/3)
log8log2 (x-5) = 2/3
log8log2 (x-5) = log8 (8^(2/3))
log8log2 (x-5) = log8(4)
log2 (x-5) = 4
log2 (x-5) = log2(2^4)
log2 (x-5) = log2(16)
x-5 =16
x=21
Проверка
log3log8log2 (21-5) = log3log8log2(16) = log3log8(4) = log3(2/3) = log3(2)-1
<span>Ответ:21 </span>
5х+3х-7=9
5х+3х=9+7
8х=16
х=16:8
х=2
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