求下列俩条平行线间的距离 3x+4y+12=0与3x+4y-3=0; 5x-12y+7=0与5x-12y-6=0

问题描述:

求下列俩条平行线间的距离 3x+4y+12=0与3x+4y-3=0; 5x-12y+7=0与5x-12y-6=0