Phương trình hoành độ giao điểm là:

`x^2=3x-2`

`<=>x^2-3x+2=0`

`<=>x^2-x-2x+2=0`

`<=>x(x-1)-2(x-1)=0`

`<=>(x-1)(x-2)=0`

`<=>`\(\left[ \begin{array}{l}x=1\\x=2\end{array} \right.\) 

`x=1=>y=1^2=1=>A(1;1)`

`x=2=>y=2^2=4=>B(2;4)`

`=>AB=sqrt((1-2)^2+(1-4)^2)=sqrt10`

`d:y=3x-2=>3x-y-2=0`

`d(O,AB) = |3.0-0-2|/sqrt(3^2+1^2)=2/sqrt10`

`=>S_(OAB) = 1/2 . d(O,AB) . AB= 1/2 . 2/sqrt10 . sqrt10=1`

`=>D`