# 2x + 5 = 47variable equations

Posted on

Hi!!  I always tell my students to pretend that we are playing a game of undo what the teacher has done in order to solve equations.

For example, in the first one you are multiplying the 2 and x and adding the 5.  To undo those operations you do the opposites.  Multiplying and dividing undo each other while adding and subtracting undo each other.  So to undo this problem we will subtract the 5 and divide the 2.  Here's how to do it step by step.

2x +5 = 47 (We always undo the number with no letter FIRST!)

2x +5 -5 = 47 -5 (Subtract the 5 to undo the adding.)

2x = 42 (-5 +5 equals 0)

Now divide by 2 to undo multiplication.

2x/2 = 42/2

x = 21

Posted on

The key to answering this kind of question is that you want to do whatever is necessary to get the unknown -- the letter -- by itself on one side of the equals sign.

2x + 5 = 47

First you want to get rid of the 5.  Subtract 5 from both sides of the equation:

2x + 5 - 5 = 47 - 5

2x             = 42

Now you need to get rid of the 2.  You can divide both sides by 2:

2x/2 = 42/2

x     =  21

Posted on

2x+5=47

2x=47-5

2x=42

X=42/2

X= 21

Posted on

2x + 5 = 47

The key finding this is to isolate x, which is unknown,

2x+5-5=47-5  (subtracting 5 on both sides)

2x=42

2x/2=42/2       (dividing both sides by 2)

Posted on

Isolate the variable first

2x + 5 = 47

Now move 5 to the other side

2x=47-5

2x=42

Now divide x by 2 to get x

x=21

Posted on

Equation:

2x+5=47

2x+[5-5]=47-5

2x=42

2x/2=42/2

x=21

Posted on

2x + 5 = 47

To solve this equation first subtract 5 from both sides

By subtracting 5 from both sides your equation should look like

2x = 42 now divide both sides from 2

By dividing both sides from 2 your equation should look like

Posted on

We want to solve for x given:

2x + 5 = 47

First, we undo any addition or subtraction: Since five is being added, we will subtract.

2x = 42

Then we undo any multiplication or division: Since two is being multiplied, we will divide.

x = 21

Posted on

2x + 5 = 47

combine the like terms by minusing 5 on each side.

2x + 5 = 47

- 5   - 5

2x = 42

now divide by 2 to get x by itself

`(2x)/2 = 42/2 `

x= 21

Posted on

2X+5=47 here are the rules to solving

Rule 1: look at the question

Rule 2: how many terms [in this case it is three]

Rule 3:Do the opposite operation of the number by 2X [the term you are solving for]. transfer the number to over the = sign

Rule 4: After the opposite operation divide the answer you got using the opposite operation with the variable you are solving for. so it is like this: 2X+5=47

opposite operation: 2x=47-5

2X=42

in order to let the x by itself divide the number by it

so 42 divided by 2 is 21.

Posted on

x=21