解
a²-1/25b²
=a²-(1/5b)²
=(a-1/5b)(a+1/5b)
m²(x-y)+n²(y-x)
=m²(x-y)-n²(x-y)
=(x-y)(m²-n²)
=(x-y)(m+n)(m-n)
16(x+y)²-25(x-y)²
=[4(x+y)]²-[5(x-y)]²
=[4(x+y)-5(x-y)][4(x+y)+5(x-y)]
=(9y-x)(9x-y)
a²-1/25 b²要运用平方差公式分解因式的方法
解
a²-1/25b²
=a²-(1/5b)²
=(a-1/5b)(a+1/5b)
m²(x-y)+n²(y-x)
=m²(x-y)-n²(x-y)
=(x-y)(m²-n²)
=(x-y)(m+n)(m-n)
16(x+y)²-25(x-y)²
=[4(x+y)]²-[5(x-y)]²
=[4(x+y)-5(x-y)][4(x+y)+5(x-y)]
=(9y-x)(9x-y)