Respuesta :
remember, you can do anything to an equation as long as you do it to both sides
assuming N=n
1n-3-4n=21
1n-4n-3=21
-3n-3=21
add 3 to both sides
-3n=24
divide both sides by -3
n=-8
assuming N=n
1n-3-4n=21
1n-4n-3=21
-3n-3=21
add 3 to both sides
-3n=24
divide both sides by -3
n=-8