ответ: - 127,75
y = √x - 16x²
y' = (√x)'-(16x²) = 1/2√x - 16•2x = 1/2√x -32x
y'(4) = 1/4 - 32•4 = 1/4 - 128 = (1-512)/4= -511/4
-511/4 = - 127,75
