What is the answer to 3x=27?

Question

I was doing a STAAR review and I came apon this question. I didn't understand it and everytime that I tried to solve it, it didn't look right. So can you please help me on this question? It's really bothering me.

Answer 1

Well to find solve the question we need to solve for x, in other words we need to get x alone on one side.

....3x=27

is the same thing as 

....3 * x = 27

so to get x alone we divide both sides by 3

3x/3=27/3

the 3's cancel out on the left side leaving you with

x=9

Answer 2

Put in other words, they are looking for a number, that when multiplied by 3, gives you 27.  So 3 times what = 27?

This problem can be solved algebraically, but first I just want to state a few key rules of algebra.

1) any number divided by it self, equals 1.  
(5 divided b 5 = 1, 1000 divided by 1000 = 1, etc..)

2) any number multiplied by 1, equals itself.
 (5 * 1 = 5,  1000 * 1 = 1000, etc..)

3) whatever you do to one side of the equation, you have to do to the other
(example, 4 = 1 + 3, which is a true statement. If I add 1 to both sides we get 4 + 1 = 1 + 3 + 1, which is still a true statement.)

So back to our problem, 3x = 27. 
All you need to do is get the x by itself, on one side of the equation. So the goal is to get that 3 away from the x. 

Suppose we took 3x and divided it by 3. Because of rule 1), we know that 3/3 = 1.
So then 3x divided by 3 = 1x
Because of rule 2) 1 * x = x, so 1x just becomes x. this is what we wanted, x by itself!

So lets take 3x = 27 and divide both sides by 3. We  have:
 3x/3 = 27/3
1x = 9
x = 9

And there you have it! I hope this helps :D

 

Answer 3

3x=27 is the same as 3 times x equals 27

Divide both sides by 3

3x/3=27/3

Since 3/3 equals one, you can leave X by itself. 

27/3 equals 9. 9 times 3 equals 27.

x=9