5c^3-625=5×c×c×c-5×5×5×5
4a^2-4ab+b^2+8a-4b=2×2×a×a-2×2×a×b+b×b+2×2×2×a-2×2×b
a^2+b^2ab+2a+2b+1=a×a+b×b×a×b+2×a+2×b+1
5c^3-625=5×c×c×c-5×5×5×5
4a^2-4ab+b^2+8a-4b=2×2×a×a-2×2×a×b+b×b+2×2×2×a-2×2×b
a^2+b^2ab+2a+2b+1=a×a+b×b×a×b+2×a+2×b+1