Find the derivative of the curve at x=5. That will be the gradient of the tangent to the curve at (5,e). The gradient is 0.2e. Next compute equation of the tangent. The tangent passes through (5,e) , (x,y), m = 0.2e. The equation is y = 0.2ex. To check if the tangent passes through the origin, check if the curve satisfies y = 0 when x = 0, since the coordinates of the origin are (0,0). So we have y = 0.2e(0) = 0. Hence we have (0,0). Thus the tangent goes through the origin.