log(10)(25/9)减log(10)(7/4)减log(10)(1/9)加1/2log(10)(49)

问题描述:

log(10)(25/9)减log(10)(7/4)减log(10)(1/9)加1/2log(10)(49)

log(10)(25/9)减log(10)(7/4)减log(10)(1/9)加1/2log(10)(49)
=log(10)(25/9÷7/4÷1/9×7)
=log(10)100
=2