Odpowiedź:
[tex]a)\ \ 3(a+2b)-(b-2a)+9(b-\frac{a}{3})=3a+6b-b+2a+9b-3a=2a+14b\\\\b)\ \ -6a+2(3a-b)-4(-2a+b)=-6a+6a-2b+8a-4b=8a-6b\\\\c)\ \ 2(x+3y)-x(3-y)+4y(1-x)=2x+6y-3x+xy+4y-4xy=-x+10y-3xy\\\\d)\ \ 2x(x+3y)-6y(x-2y)-8y^2=2x^2+6xy-6xy+12y^2-8y^2=2x^2+4y^2\\\\e)\ \ xy-x(3xy+y)+y(-2x+4x^2)=xy-3x^2y-xy-2xy+4x^2y=x^2y-2xy\\\\f)\ \ -x^2(y-xy)-xy(2x^2-x-y^2)=-x^2y+x^3y-2x^3y+x^2y+xy^3=-x^3y+xy^3[/tex]
