If the equation is d/0.2 = 3d+2.1 what number does d represent? !

Here's how to find out:

Take the equation:                        d/0.2  =  3d + 2.1

Multiply each side by  0.2 :           d        =  0.6d + 0.42

Subtract  0.6d  from each side:     0.4d   =           0.42

Divide each side by  0.4 :                 d  =           1.05


This answer has been changed.
I got  d = -0.75 the first time.
Then I came back and changed it.
It's correct now.        d = 1.05

The length is 7.5 because 9x5 is 45 /6 is 7.5m