(2x-6)/(x²-4x+4)÷(3-x)/(x²+6x+9)×(2-x)/(x+3)
=2（x-3)/(x-2)^2 X(x+3)^2/(3-x) X(2-x)/(x+3)
=2（x-3)/(x-2)^2 X(x+3)^2/(x-3) X(x-2)/(x+3)
=2(x+3)/x-2