Đáp án+Giải thích các bước giải:
c)
`\sqrt{\frac{64}{81}}-|-2020/2021|+(-1/3)^2`
`=\sqrt{\frac{64}{81}}-2020/2021+1/9`
`=\sqrt{\frac{8^2}{9^2}}-2020/2021+1/9`
`=\sqrt{(\frac{8}{9})^2}-2020/2021+1/9`
`=|\frac{8}{9}|-2020/2021+1/9`
`=(\frac{8}{9}+1/9)-2020/2021`
`=1-2020/2021`
`=2021/2021-2020/2021`
`=1/2021`