Answer:
n=3
Step-by-step explanation:
3(n+4)=21
First Step: Divide 3 on both sides
n+4=7
Second Step: Subtract 4 from both sides
[tex]n = 3[/tex]
[tex]3(n + 4) = 21 \\ 3n + 12 = 21 \\ 3n = 21 - 12 \\ 3n = 9 \\ \frac{3n}{3} = \frac{9}{3} \\ n = 3[/tex]
