Đáp án:
`4, (5/ 3)^100 . (3/5)^98 - (2/3)^100 : (2/3)^98`
`= (5/3)^100 : (5/3)^98 - (2/3)^100 : (2/3)^98`
`= (5/3)^(100 -98) - (2/3)^(100 - 98)`
`= (5/3)^2 - (2/3)^2`
`= (5^2)/(3^2) - (2^2)/(3^2)`
`= 25/9 - 4/9 = 21/9`
`= 7/3`
`5, (7/3)^99 . (3/7)^98 - (4/5)^2 : (8/25)^2`
`= (7/3)^99 : (7/3)^98 - (4/5 : 8/25)^2`
`= (7/3)^(99 - 98) - (4/5 . 25/8)^2`
`= (7/3)^1 - (5/2)^2`
`= 7/3 - 25/4`
`= 28/12 - 75/12`
`= -47/12`
