已知A=2x的平方+xy+3y的平方与B=x的平方-xy+2y的平方,求a-b和a+b

2025-02-23 00:20:06
推荐回答(3个)
回答1:

A=2x^2+xy+3y^2
B=x^2-xy+2y^2
A+B=2x^2+xy+3y^2+x^2-xy+2y^2
=3x^2+5y^2
A-B=2x^2+xy+3y^2-(x^2-xy+2y^2)
=2x^2+xy+3y^2-x^2+xy-2y^2
=x^2+2xy+y^2

回答2:

a=2x^2+xy+3y^2
b=x^2-xy+2y^2
a-b=x^2+2xy+y^2
a+b=3x^2+5y^2

回答3:

A+B=2x^2+xy+3y^2+x^2-xy+2y^2
=3x^2+5y^2
A-B=2x^2+xy+3y^2-(x^2-xy+2y^2)
=2x^2+xy+3y^2-x^2+xy-2y^2
=x^2+2xy+y^2