найдите производные
1.
[tex] y = \frac{2 {x}^{3} }{1 - 7x} [/tex]
2.
[tex]y = {x}^{4} + 4 {x}^{3} - 8 {x}^{2} - 5[/tex]

y'=[ 6x^2*(1-7x) - 2x^3*(-7) ] / (1-7x)^2 =

=[ 6x^2-42x^3+14x^3 ] /(1-7x)^2 = [ 6x^2-28x^3 ] /(1-7x)^2

y'=4x^3+12x^2-16x