因式分解:
(1)3a2﹣27
(2)a3﹣2a2+a
(3)(x2+y2)2﹣4x2y2
(4)a2(x﹣y)+16(y﹣x)
解:(1)3a2﹣27
=3(a2﹣9)
=3(a+3)(a﹣3);
=a(a2﹣2a+1)
=a(a﹣1)2;
=(
Two months quite a long time.
历史上第一个圆了人类飞上蓝天的梦想而被称为“航天飞行器的先驱”的是( )