б) (ex·cos x)' = (ex)'·cos x + ex·(cos x)' = ex·cos x + ex(–sin x) = ex·(cos x – sin x)
в) (\frac{4x+4}{2x-3})' = \frac{(4x+4)'(2x-3) - (4x+4)(2x-3)'}{(2x-3)^2} = \frac{4(2x-3) - 2(4x+4)}{(2x-3)^2} = \frac{8x-12 - 8x-8}{(2x-3)^2} = \frac{-20}{(2x-3)^2}
г) (\ln(3x-7))' = \ln'(3x-7) \cdot (3x-7)' = \frac{1}{3x-7} \cdot 3 = \frac{3}{3x-7}