Answer :
First, let's start by carefully breaking down the given expression:
[tex]\[ (9mn - 19m^4n) - (8m^2 + 12m^4n + 9mn) \][/tex]
We need to distribute the negative sign across the second set of parentheses:
[tex]\[ = 9mn - 19m^4n - (8m^2 + 12m^4n + 9mn) \][/tex]
[tex]\[ = 9mn - 19m^4n - 8m^2 - 12m^4n - 9mn \][/tex]
Notice that [tex]\(9mn\)[/tex] and [tex]\(-9mn\)[/tex] cancel each other out:
[tex]\[ = -19m^4n - 8m^2 - 12m^4n \][/tex]
Combine like terms:
[tex]\[ = (-19m^4n - 12m^4n) - 8m^2 \][/tex]
[tex]\[ = -31m^4n - 8m^2 \][/tex]
Thus, the simplified expression is:
[tex]\[ m^2(-31m^2n - 8) \][/tex]
So, the correct answer is:
C. [tex]\(-31m^4n - 8m^2\)[/tex]
[tex]\[ (9mn - 19m^4n) - (8m^2 + 12m^4n + 9mn) \][/tex]
We need to distribute the negative sign across the second set of parentheses:
[tex]\[ = 9mn - 19m^4n - (8m^2 + 12m^4n + 9mn) \][/tex]
[tex]\[ = 9mn - 19m^4n - 8m^2 - 12m^4n - 9mn \][/tex]
Notice that [tex]\(9mn\)[/tex] and [tex]\(-9mn\)[/tex] cancel each other out:
[tex]\[ = -19m^4n - 8m^2 - 12m^4n \][/tex]
Combine like terms:
[tex]\[ = (-19m^4n - 12m^4n) - 8m^2 \][/tex]
[tex]\[ = -31m^4n - 8m^2 \][/tex]
Thus, the simplified expression is:
[tex]\[ m^2(-31m^2n - 8) \][/tex]
So, the correct answer is:
C. [tex]\(-31m^4n - 8m^2\)[/tex]