Tìm x: 5/3.(4/5x - 2/5) + (3 - 2/3x).1/2 = -4/7

bài 11: tìm x
5/3 . (4/5x-2/5) + (3-2/3.x) . 1/2 =-4/7

bài 12: tìm x
-1/2 (3-5x) - 5. (3/4 x-1) = 5/2 . (x+ 2/3)