X/3+x/6+x=-9/2 28/x-8=1 x-7/x-15=3 11-x/5=x/6 x²-8x=0

1) х/3 + x/6 + x = - 9/2, найдем общий знаменатель он будет равняться 6:

(2x + x + 6x) / 6 = - 9/2, 9x / 6 = - 9/2, 3x / 2 = - 9/2, 3 х = - 9, х = - 3;

2) 28 / x - 8 = 1, (28 - 8 х) / x = 1, 28 - 8 х = x, 28 = x + 8x, 28 = 9x, x = 28/9;

3) x - 7/x - 15 = 3, x - 7/x - 15 = 3, х^2 - 7 - 15x = 3, х^2 - 7 - 15x - 3 = 0, х^2 - 15x - 10 = 0

4) 11 - x/5 = x/6, 11 = x/6 - x/5, 11 = (5 х - 6 х) / 30, 330 = - х, х = 330;

5) x² - 8x = 0, х (х - 8) = 0, x1 = 0, x2 = x - 8 = 8.