To differentiate y with respect to x, you have to multiply each x term by their respective power and then decrease their power by one. For example, 4x2 differentiated is 2 x 4x2-1 = 8x. So, splitting this problem into parts, 15x3 differentiated is 3 x 15x3-1 = 45x2, and 24x2 differentiated is 48x. 6 doesn't involve x so it cannot be differentiated with respect to it. Hence, dy/dx = 45x2 + 48x.