设(3m+2n)^2=(3m=2n)^2+P的值是A.12mn B.24mn C.6mn D.48mn

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设(3m+2n)^2=(3m=2n)^2+P的值是A.12mnB.24mnC.6mnD.48mn设(3m+2n)^2=(3m=2n)^2+P的值是A.12mnB.24mnC.6mnD.48mn设(3m

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