(b-4)²=b²-2×b×4+4²=b²-8b+16
(5a-10b)²=(5a)²-2×5a×10b+(10b)²=25a²-100ab+100b²
(3n³-4mn²)²=(3n³)²-2×3n³-4mn²+(4mn²)²=9n⁶-24mn⁵+16m²n⁴
(b-4)²=b²-2×b×4+4²=b²-8b+16
(5a-10b)²=(5a)²-2×5a×10b+(10b)²=25a²-100ab+100b²
(3n³-4mn²)²=(3n³)²-2×3n³-4mn²+(4mn²)²=9n⁶-24mn⁵+16m²n⁴