Answer:
1.3b
Explanation:
The equation is -2.6+3.9b. A negative number acts like subtraction, so we would subtract 2.6 from 3.9 to get 1.3. The b is still there, and we don't know what it is, so we simplify the equation to 1.3b.
Sorry, this explanation isn't the best. Hope it helped! :)