How do you solve 3x+1=12?

2 Answers
Oct 8, 2015

x=16

Explanation:

Subtract 1 from both sides

3x+11=121

3x=12

And then divide both sides by 3

3x3=123

12 divided by 3 can also be written as 12 multiplied by 13

x=(12)13

x=16

** *** OR in simpler terms *** **

Bring 1 to the other side, making sure to change its sign

3x=121

3x=12

And divide both numerators by 3

3x3=123

x=16

Oct 8, 2015

x=16

Explanation:

People use the term "balance the equation" to describe how to solve this. Consider 5 = 5. Which is true. Write it as (5) = (5), the brackets are only there to show what is the original 'elements' of the equation as a group. Now consider the false statement that (5) -1 = 5. To balance this we need to write (5) -1 = (5) - 1. We have applied the same process to both sides.

Solving the original equation using the same idea:
The target is to get x on one side of the equals sign and everything else on the other.

First isolate all the elements with x in them. That is "3x"

(3x+1)=(12)

Step1. Subtract 1 from both sides giving:
(3x+1)1=(12)1
3x=12

Step2. Now we need to separate the 3 from the x and move it to the other side of the equals sign. This is done by changing 3 into 1 as 1×x=x. Dividing by three is the same as multiply by 13.

Divide both sides by three

(3x)×13=(12)×13

33×x=1×12×3

thus x=16