Chapter 2 - Solving Equations - 2-7 Solving Proportions - Practice and Problem-Solving Exercises - Page 128: 48

$b=-3$

We see that the variable only appears in the numerator of the fractions, so we know that the Multiplication Property of Equality will work well. We multiply both sides of the equation by 6 to obtain that $3b+39=-10b$. We first cancel out addition by subtracting both sides by 3b to get that $39=-13b$. We then divide by -13 on both sides to isolate b and find that $b=-3$.