﹙4b+2a﹚/﹙9b-6a﹚ - ﹙4a-6b﹚/﹙3a+6b﹚
=2﹙a+2b﹚/[﹣3﹙2a-3b﹚] -2﹙2a-3b﹚/3﹙a+2b﹚
=﹣2/3 ×3-2/3×1/3
=﹣2-2/9
=﹣20/9.