因式分解:3x2+4xy-y2.
问题描述:
因式分解:3x2+4xy-y2.
答
3x2+4xy-y2
=3(x2+
xy-4 3
y2)1 3
=3[(x2+2×
xy+2 3
y2)-4 9
y2-1 3
y2]4 9
=3[(x+
y)2-2 3
y2]7 9
=3(x+
y+2 3
y)(x+
7
3
y-2 3
y)
7
3
=3[x+
y)(x-2+
7
3
y).2−
7
3