the slope of the line is given by the derivative
m = dy/dx = 4x^3 + 2e^x
using the point slope form of a straight line
y - y1 = m(x - x1) where m is the above and (x1,y1) is the point of contact of the tangent we have
y - y1 = (4x^3 + 2e^x)(x - x1) which is equation of the tangent
