`a,`
`A = \sqrt{3-2\sqrt{2}} + \sqrt{3+2\sqrt{2}}`
`= \sqrt{2} - 1 + \sqrt{2}+1`
`= 2\sqrt{2} - 1 + 1`
`= 2\sqrt{2}`
`b,`
`|x-1|=2021`
`⇔ x - 1 = \pm2021`
Trường hợp 1 :
`x - 1 = -2021`
`⇔ x = -2021 - 1`
`⇔ x = -2020`
Trường hợp 2 :
`x - 1= 2021`
`⇔ x = 2021 + 1`
`⇔ x = 2022`