BIue one year ago What is 7(n+4) = 21 equal to?

1. geerky42

Solve for n? Divide both sides by 7, then subtract both sides by 4.

2. BIue

7(n+4) = 21 Choices. n = -1 n = 7 n = 10 n = 1 Im having trouble :/

3. BIue

@geerky42

4. geerky42

You want to isolate n. So first you need to "remove" 7. w can do that by divide it by 7, but we must do that to 21 too. $7(n+4)=21\quad\Longrightarrow\quad\dfrac{7(n+4)}7=\dfrac{21}7$

5. geerky42

Then we are left with $$n+4 = 3$$.

6. BIue

Ok.

7. BIue

So n = 7? Im not really good with mathematics sorry.

8. geerky42

n is still not isolated, so we need to remove 4. Opposite of adding 4 is subtracting 4. So we subtract $$n+4$$ by 4, do the same to 3. $n+4=3\quad\Longrightarrow\quad n+4-4=3-4$ $\boxed{n=-1}$

9. BIue

Thank you.