(5m+3n)^2-(m-3n)(25m-3n),其中m=1,n=2

题目

(5m+3n)^2-(m-3n)(25m-3n),其中m=1,n=2

答案

答：
(5m+3n)^2-(m-3n)(25m-3n),其中m=1,n=2
=25m²+30mn+9n²-(25m²-3mn-75mn+9n²)
=30mn+78mn
=108mn
=108×1×2
=216