(9/8)/x-(3/4)*(4/7)=15/14
9/8x-3/7=15/14
9/8x=15/14+3/7
9/8x=15/14+6/14
9/8x=21/14
9/8x=3/2
8x*3=9*2
24x=18
x=18/24
x=3/4