Mong các bạn giúp mink ạ

Đáp án:

`b)`

`(x+2).(x+3)`

`=x.(x+3)+2.(x+3)`

`=x^{2}+3x+2x+6`

`=x^{2}+5x+6`

`c)`

`(35x^{5}y^{3}-28x^{7}y^{2}):7x^{3}y^{2}`

`=(35x^{5}y^{3}:7x^{3}y^{2})-(28x^{7}y^{2}:7x^{3}y^{2})`

`=[(35:7).(x^{5}:x^{3}).(y^{3}:y^{2})]-[(28:7).(x^{7}:x^{3}).(y^{2}:y^{2})]`

`=5x^{2}y-4x^{4}`