Answer:
Step-by-step explanation:
First, let's get common denominators for both fractions -- in this case, the least common multiple of [tex]4[/tex] and [tex]6[/tex] is [tex]12[/tex].
[tex]-\frac{15}{4}b + \frac{5}{6}b[/tex]
[tex]-\frac{45}{12}b + \frac{10}{12}b[/tex]
Combining the terms together by adding the numerators will give us the answer:
[tex]\frac{-45 + 10}{12}b[/tex]
[tex]-\frac{35}{12}b[/tex]