giúp em với ạ hứa 5 sao với ctlhn

`a)A={1;2;3}`

`B={n∈N|n<4}`

`→B={0;1;2;3}`

`C=(0;+∞)`

`D={x∈R|2x^2-7x+3=0}`

`**2x^2-7x+3=0`

`⇔2x^2-x-6x+3=0`

`⇔x(2x-1)-3(2x-1)=0`

`⇔(x-3)(2x-1)=0`

`⇔x=3;x=1/2`

`→D={1/2;3}`

`→A⊂B;A⊂C;D⊂C`

`b){1;2}⊂X⊂{1;2;3;4;5}`

`→X={1;2}`

`X={1;2;3}`

`X={1;2;3;4}`

`X={1;2;3;4;5}`