3 – 27(x – y)3] ÷ (5Y – x) = Ax2 + Bxy + Cy2 ∴ A + B + C = 16Detailed Solution∶⇒ [8(x + y)3 – 27(x - y)3] ÷ (5y - x) = Ax2 + Bxy + Cy2⇒ [{2(x + y)}3 – {3(x – y)}3] ÷ (5y – x) = Ax2 + Bxy + Cy2⇒ {2(x + y)} – {3(x – y)} [{2(x + y)}2 + 2(x + y)3(x – y) + {3(x – y)}2] ÷ (5y – x) = Ax2 + Bxy + Cy2⇒ (5y – x) [4x2 + 4Y2 + 8xy + 6x2 – 6Y2 + 9x2 + 9y2 – 18xy] ÷ (5y – x) = Ax2 + Bxy + Cy2⇒ 19x2 – 10xy + 7y2 = Ax2 + Bxy + Cy2On comparing⇒ A = 19, B = -10 and C = 7⇒ (A + B + C) = 19 + 7 – 10 = 16