Question

4n + 5n= -9? What is the answer?

Answer 1

add 4n and 5n, which is 9. 9n=-9, and if u divide both sides by nine, n=-1

Answer 2

Combine like terms:

$4n+5n=-9\\ 9n=-9$

Isolate the variable on one side of the equation:

$9n=-9\\ n=-1$

The answer is $n=-1$.