3 + (√b)3 = 32a√b + b√a = 31√a√b(√a + √b) = 31Suppose √a = x and √b = yx3 + Y3 = 32 ---- (1)xy(x + y) = 31 ---- (2)(x + y)3 = x3 + y3 + 3xy(x + y)(x + y)3 = 32 + 3 × 31 = 125 = 53(x + y) = 5x3 + y3 = (x + y)(x2 + y2 – xy) = 32(x + y)(x2 + y2 – xy(x + y) = 325(x2 + y2) – 31 = 32(x2 + y2) = 63/5(a + b) = 63/55(a + b)/7 = (5/7) × (63/5) = 9