把3x^2+12xy+11y^2因式分解

问题描述:

把3x^2+12xy+11y^2因式分解

3x^2+12xy+11y^2
=3x^2+12xy+12y^2-y^2
=3(x+2y)^2-y^2
=[a(x+2y)+y][a(x+2y)-y]
a=根号3