计算:3(y-z)^2-(2y+z)(-z+2y)

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/23 14:35:27
计算:3(y-z)^2-(2y+z)(-z+2y)计算:3(y-z)^2-(2y+z)(-z+2y)计算:3(y-z)^2-(2y+z)(-z+2y)3(y-z)^2-(2y+z)(-z+2y)=3(

计算:3(y-z)^2-(2y+z)(-z+2y)
计算:3(y-z)^2-(2y+z)(-z+2y)

计算:3(y-z)^2-(2y+z)(-z+2y)
3(y-z)^2-(2y+z)(-z+2y)
=3(y-z)^2-(2y+z)(2y-z)
[平方差公式]
=3(y-z)^2-[(2y)^2-z^2]
[完全平方公式]
=3(y^2-2yz+z^2)-4y^2+z^2
=-y^2-6yz+4z^2

3(y-z)^2-(2y+z)(-z+2y)
=3y^2-6yz+3z^2-4y^2+z^2
=-y^2-6yz+4z^2

3(y-z)^2-(2y+z)(-z+2y)
=3(y-z)^2-(2y+z)(2y-z)
=3(y-z)^2-[(2y)^2-z^2]
=3(y^2-2yz+z^2)-4y^2+z^2
=-y^2-6yz+4z^2