Question

数学高手进来解几道因式分解的题目

﹙1﹚121﹙x-y﹚²－169﹙x+y﹚² ﹙2﹚x﹙n-1﹚²-2x﹙n-1﹚＋x
﹙3﹚a²﹙x+3﹚－b²﹙x+3﹚ ﹙4﹚a³-9a

Answer 1

121﹙x-y﹚²－169﹙x+y﹚²
=[11（x-y）+13（x+y）][11(x-y)-13(x+y)]
=(24x+2y)(-2x-24y)
=-4(12x+y)(x+12y)
x﹙n-1﹚²-2x﹙n-1﹚＋x
=x[﹙n-1﹚²-2﹙n-1﹚＋1]
=x(n-1-1)²
=x(n-2)²
a²﹙x+3﹚－b²﹙x+3﹚
=(a²－b²)﹙x+3﹚
=(a-b)(a+b)(x+3)
a³-9a
=a(a²-9)
=a(a-3)(a+3)