因式分解4x^2+12xy+7y^2

问题描述:

因式分解4x^2+12xy+7y^2

4x^2+12xy+7y^2
=4(x^2+3xy)+7y^2
=4(x+3y/2)^2-4*9/4y^2+7y^2
=4(x+3y/2)^2-2y^2
=(2x+3y+√2y)*(2x+3y-√2y)