Tìm x biết

2/15 : ( 1/3 • 6/5 - 1/3 • 4/5 ) 5/7 • 2/11 + 5/7 • 9/11 + 12/7 2/3 • x -1/2 = 5/6 7/15 : ( 5/9 - x ) = 9/10