Question 77177
solve: 
3x/7 - 5x/3 = 2/21
;
21(3x/7) - 21(5x/3) = 21(2/21); this is right
:
You should have:
3(3x) - 7(5x) = 2
:
9x - 35x = 2
:
-26x = 2
:
x = 2/-26
:
x = -1/13
:
I check the solution using a calc