<u>Explanation</u> In this question you are expected to expand (5c+2/3)(5c-2/3) (5c+2/3)(5c-2/3)=(5c×5c)-(5c×2/3)+(5c×2/3)-(2/3×2/3) =25c^2-10c/3+10c/3-4/9 25c^2-4/9 The expanded form of (5c+2/3)(5c-2/3) is 25c^2-4/9 and this is what the question requires of you to do.</span>