Question 196330
Your equation is ambiguous.  People reading it can interpret it in potentially more than one way.  Correct me if I interpreted your problem wrong.
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Starting with:
-3 1/2x + 2 3/4 + 1/2x = 3 7/8 
Your first step is to change the mixed numbers into improper fractions:
-3 1/2 = -(6/2 + 1/2) = -7/2
2 3/4 = 8/4 + 3/4 = 11/4
3 7/8 = 24/8 + 7/8 =  31/8
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Now, we can rewrite:
-3 1/2x + 2 3/4 + 1/2x = 3 7/8 
As
(-7/2)x + 11/4 + (1/2)x = 31/8 
Multiply both sides by 8 to get rid of all denominators:
8[(-7/2)x + 11/4 + (1/2)x] = 8[31/8]
-28x + 22 + 4x = 31 
-24x + 22 = 31 
22 = 24x + 31
-9 = 24x
-9/24 = x
-3/8 = x