设(3m+2n)^2=(3m=2n)^2+P的值是A.12mn B.24mn C.6mn D.48mn
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/02 13:04:35
![设(3m+2n)^2=(3m=2n)^2+P的值是A.12mn B.24mn C.6mn D.48mn](/uploads/image/z/3511495-55-5.jpg?t=%E8%AE%BE%EF%BC%883m%2B2n%29%5E2%3D%283m%3D2n%29%5E2%2BP%E7%9A%84%E5%80%BC%E6%98%AFA.12mn+B.24mn+C.6mn+D.48mn)
设(3m+2n)^2=(3m=2n)^2+P的值是A.12mn B.24mn C.6mn D.48mn
设(3m+2n)^2=(3m=2n)^2+P的值是
A.12mn B.24mn C.6mn D.48mn
设(3m+2n)^2=(3m=2n)^2+P的值是A.12mn B.24mn C.6mn D.48mn
∵(3m+2n)^2=9m^2+12mn+4n^2
又∵(3m-2n)²=9m^2-12mn+4n^2
∴P=(3m+2n)^2-(3m-2n)²=9m^2+12mn+4n^2-(9m^2-12mn+4n^2)=24mn
∴选B
(3m+2n)^2=(3m-2n)^2+P
B