9(a-b)²-16(a+b)²=9a²-18ab+9b²-16a²-32ab-16b²=-7a²-50ab-7b²=-(7a²+50ab+7b²）=-(7a+b)(a+7b)9(a-b)²-16(a+b)²=[3(a-b)]²-[4(a+b)]²=[3(a...