Find the best quadratic approximation, Q(x, y) of √9 - 7x + 4y for (x, y) 7x+4y near (0,0), Q(x, y): =

A path of a toy rocket thrown upward from the ground at a rate of 208 ft/sec is modeled by the quadratic function of. h(x)=16t2+208t. When will the rocket reach its maximum height? What will be the maximum height?

Find two nonnegative number x and y for which x+3y=30, such that x2y is maximized.

Find the cubic polynomial function f with real coefficients that has 1 and 2+i as zeros, and f2=2.