(Applications of Differentiations) Please answer the following!!!!URGENT!!Thankyou

I point Find the Local Linear Approximation of f(x) = va at x0 = 1. Express the number 10 as a sum of two nonnegative numbers whose product is as large as possible. Let f(x) = 3x4+ 4x3 - 12x2. Find the interval on which f is decreasing. In f(x) = x' + -, find k so that f has a critical number at a = 3. Let f(x) = 3x4 + 4x3 - 12x2. Find the interval on which f is increasing. Divide the number 12 into two parts such that the product of one part and the square of the other part is maximum. An open box is to be made from a 16-inch by 30-inch piece of cardboard by cutting out squares of equal size from the four corners and bending up the sides. What size should the squares be to obtain a box with the largest volume? Assume that oil spilled from a ruptured tanker spreads in a circular pattern whose radius increases at a constant rate of 3ft/s. How fast is the area of the spill increasing when the radius of the spill is 50 ft