使用公式
log(a)M+log(a)N=log(a)[MN]
log(a)M-log(a)N=log(a)[M/N]
log(2/3)81-log(2/3)16+log(2/3)20-log(2/3)30
=log(2/3)(81/16×20/30)
=log(2/3)[(3/2)⁴×2/3]
=log(2/3)[(3/2)³]
=3log(2/3)[3/2]
=3×(-1)
=-3
不明追问
使用公式
log(a)M+log(a)N=log(a)[MN]
log(a)M-log(a)N=log(a)[M/N]
log(2/3)81-log(2/3)16+log(2/3)20-log(2/3)30
=log(2/3)(81/16×20/30)
=log(2/3)[(3/2)⁴×2/3]
=log(2/3)[(3/2)³]
=3log(2/3)[3/2]
=3×(-1)
=-3
不明追问