12ab{2a-3/4(a-b)+2/3b}

问题描述:

12ab{2a-3/4(a-b)+2/3b}

12ab{2a-3/4(a-b)+2/3b}
=12ab{2a-3/4a+3/4b+2/3b}
=12ab{5/4a+17/12b}
=15a²b+17ab²