Pre-Calculus apparantely so I thought it'd go here anyways

Rate of Change problem using the equation [f(a+h) - f(a)] / h to find the instantaneous velocity.

f(x) = (3s^3 - s^2 + 5s) / (s^3 + 10), s = 1.5

I need the slope of the tangent when s = 1.5

Can't use derivatives, says the teacher