将下列各式因式分解。★★★★★

Question

1.-a^2+b^2
2.49x^2-z^2
3.16m^2-25n^2

Answer 1

1.-a^2+b^2=(b+a)(b-a)
2.49x^2-z^2=(7x+z)(7x-z)
3.16m^2-25n^2=(4m+5n)(4m-5n)

Answer 2

1.-a^2+b^2=(a+b)(-a+b)
2.49x^2-z^2=(7x+z)(7x-z)
3.16m^2-25n^2=(4m+5n)(4m-5n)

Answer 3

1.-a^2+b^2=-(a+b)(a-b)
2.49x^2-z^2=(7x+z)(7x-z)
3.16m^2-25n^2=(4m+5n)(4m-5n)

Answer 4

①-a^2+b^2=(a+b)(-a+b)
②49x^2-z^2=(7x+z)(7x-z)
③16m^2-25n^2=(4m+5n)(4m-5n)
这些都是平方差的问题，很基本的...
看来你需要多加练习啊~ ^_^