10. y=a+b1f1(x)+b2 f2(x)++bn fn(x) 令 ui= fi(x, 则有 y=a+b1u1++bnun. 20. y=a ebx . 令 z=ln y, 则有 z = ln a + b x = a* + b x . 30. y = a xb . 令 z = ln y, u = ln x, 则有 z = ln y = lnb ln x = a*+ b u 40. y = 1