y = x( 3x - 7 )^3
dy/dx = d(x)*(3x - 7 )^3 + x * d((3x - 7 )^3)
dy/dx = ( 3x - 7 )^3 + x( 3(3x - 7 )^2*d(3x - 7))
dy/dx = ( 3x - 7 )^3 + x(3( 3x - 7 )^2 * 3)
dy/dx = ( 3x - 7 )^3 + 9x(3x - 7 )^2
dy/dx = ( ( 3x - 7 ) ^2)* [( 3x - 7 ) + 9x]
dy/dx = ((3x - 7 )^2) * (12x -7)