Please help me need help

Which is the completely factored from of xy^3-x^3y

Maria donates a fixed amount, a, to a charity each month. if she donates $300 in 12 months, what is the equation for a? a. a + 300 = 12 b. a × 300 = 12 c. a × 12 = 300 d. a + 12 = 300 e. a + 32 = 100

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way