Let us start by graphing these points on a coordinate plane.(See picture) So, we can see that (-15,21) is in the 2nd quadrant. (4.5,10.6) is in the 1st quadrant. (-3/4,-4 1/9) is in the third quadrant.And finally, (3,-7) is in the 4th quadrant. Then we come to our y axis and the x axis. On the y axis we have (0,12)and on the x axis we have (18,0). Hope this helps!