(1) let f (x) = (2x-2)/e x make f' (x) = (2ex-2xex+4e x)/(e x)?

=(4-2x)/e^x=0

x=2，f(2)=2/e？ .

(2) by (ax-a)/e x+ 1 = 0.

a=-e^x/(x- 1)

a′=-e^x(x-2)/(x- 1)？

When x=2, the function has no intersection with the x axis.

a=-e？ ,∴a∈[-e？ ,0)∪(0,+∞)