长方形面积是3a2-3ab+6a,一边长为3a,则它的周长是_.
问题描述:
长方形面积是3a2-3ab+6a,一边长为3a,则它的周长是______.
答
它的周长是:2[(3a2-3ab+6a)÷3a+3a]
=2(a-b+2+3a),
=2(4a-b+2),
=8a-2b+4.