Find a simple function g of the smallest order so that f(x) is big-O of g(x). In your estimation you can use theorems learned in lecture about the big-O estimates of sums/products of functions. f(x) = (x 2.3 + x ln x 5 )(1.1 x+1 + 1.2 x ) + (x 2 + 1.2 x )(x 3 + 0.92x )