Question

因式分解：9（m+n）² -16（m-n）²

Answer 1

您好！
9(m+n)²-16(m-n)²
=[3(m+n)]²-[4(m-n)]²
=[3(m+n)+4(m-n)][3(m+n)-4(m-n)]
=(3m+3n+4m-4n)(3m+3n-4m+4n)
=(7m-n)(7n-m)

这里主要考察平方差公式：a²-b²=(a+b)(a-b)

祝你学习进步O(∩_∩)O哈！

Answer 2

9(m+n)^2-16(m-n)^2=[3(m+n)-4(m-n)][(3(m+n)+4(m-n)].
=(-m+n)(7m-n).

Answer 3

9（m+n）² -16（m-n）²
=(3m+3n)²-(4m-4n)²
=(3m+3n+4m-4n)(3m+3n-4m+4n)
=(7m-n)(-m+7n)

Answer 4

9（m+n）² -16（m-n）²
=(3m+3n-4m+4n)(3m+3n+4m-4n)
=(-m+7n)(7m-n)

Answer 5

[3（m+n)+4(m-n)]{3(m+n)-4(m-n)}