三分之七括号的5次方乘以二十一分之八括号的零次方除以九分之七括号的四次方
=(7/3)^5 *(8/21)^0 /(7/9)^4
=(7/3)^5 /(7/9)^4
=(7^5/3^5) *(9^4/7^4)
=7^(5-4)*3^(8-5)
=7*3^3
=7*27
=169