How do you solve 3-3a=21?

Answer 1

3 - 3a = 21

3 - 3a - 3 = 21 - 3

- 3a = 18

- 3a/- 3 = 18/- 3

a = 18/- 3

a = - 6

The answer is a = - 6

Insert the a value into the equation
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Check

3 - 3a = 21

3 - 3( - 6) = 21

3 - (- 18) = 21

3 + 18 = 21

21 = 21

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Answer 2

Alright. Your equation is 3-3a=21. First, to get your a term alone (which you have to do to logically solve this problem), you have to subtract three from both sides.

3-3-3a=21-3. -3a=18

We get -3a on the left side, and since 21-3=18, we get -3a=18. Next, to get a alone, thus solving for a, we divide both sides by -3.

-3a/-3=18/-3. a=18/-3. a=-6.

Since -3a/-3 is of course a, and 18/-3 is the same as -18/3, you get a=-6, because 18/3=6, and since there's a negative sign in front of the 18/3, it becomes -6.
So, your answer is a=-6 or -6.
There you go. I'm glad I could help. :)

Answer 3

You need to get all the "known numbers" on one side of the equations. So firstly minus the 3 (because of the left of the equation it's positive, so do the opposite to get rid of it) from the right, making the equation "-3a = 18". Make the left positive, changing it to "3a", but you'll have to swap the right too, making it "3a = -18", divide -18 by 3, making -6. So "a = -6".

Answer 4

First, subtract 3 from both sides:

3 - 3 - 3a = 21-3

So then you get,

-3a = 18

Then to get a divide both sides by -3

-3a/-3 = 18/-3

And you get

a = -6

Hope that helps!

Answer 5

3-3a=21
-3 -3
-3a=18
a= -6

Answer 6

solving for a;

subtract 3 from both sides.

-3a=21-3 or 18.

divide both sides by -3.

a=18/-3, a=-6

a=-6

Answer 7

3-3a=21
-3a=21-3
-3a=18
a=18/-3
a=-6

Answer 8

add 3 to 21
3+21= 24
24=3a
24 divided by 3 equals 8 and
3a divided by 3 equals a
a=8

Answer 9

-3a=21-3
a=18/-3
a=-6

Answer 10

3(1-a)=21
1-a=3
a=-2