Circle A has a radius of (x + 4) units. A larger circle, B, has a radius of (x + 7) units. Part 1: Use the formula for the area of a circle (A_{Circle}=\pi r^2A C i r c l e = π r 2, where r is the radius) to write an expression for the difference in the areas of circles A and B given a common placeholder variable x rather than any specific number. Simplify your expression as much as possible, but leave your answer in terms of π and x. Show all of your simplification steps and explain your process in words.

Part 2: Use your final expression from Part 1 to find the difference in the areas for circles A and B when x = 10. You can use 3.14 for π and approximate your final answer to the nearest whole number. Show all of your simplification steps and explain your process in words.