`a) 3^6 :3^5 `
`=>3^6=3.3.3.3.3.3=729`
`=>3^5=2.2.2.2.2=243`
`=>729:243=3`
`hoặc` `3^6:3^5=`$3^{6-5}$ `=3^1=3`
`Vậy` `câu` `a` `=` `3`
`b) 5^7:5^2`
`=>5^7=5.5.5.5.5.5.5=78125`
`=>5^2=5.5=25`
`=>78125:25=3125`
`hoặc` `5^7:5^2=`$5^{7-2}$ `=5^5=125`
`Vậy` `câu` `b` `=` `3125`
`c) 14^ 4 :2^3:7^4`
`=>2^4. 7^4:2^3:7^4`
`=>2^4:2^3`
`=>$2^{4-3}$
`=>2`
`Vậy` `câu` `c` `=` `2`