Question

if a+b+c=9 find (3-a)³+(3-b)³+(3-c)³-3(3-a)(3-b)(3-c)

Answer 1

a+b+c=9
9–(a+b+c) = 0
(3–a)+(3–b)+(3–c) = 0

if x + y + z = 0 then x³+ y³ + z³ – 3xyz = 0

(3–a)³+(3–b)³+(3–c)³–3(3–a)(3–b)(3–c) = 0