Solution by all methods

First of all, it's worth remembering that a first-degree equation with one variable is essentially an equation where the highest "power" is $1$. This means it is not an equation with a number or variable squared or raised to higher powers. Additionally, it contains only one variable – usually $X$. The $X$ may appear multiple times in the exercise, but it will always be the same $X$ and not $X$ and $Y$, for example.
The solution to these equations is simply to find $X$ and understand what it equals.
Examples of first-degree equations with one variable:
$3X+5=20$
$4*(x+2)-2x=12$
And now? On to the solution methods!

The logic in this solution is simply to keep the variable $X$ on one side of the equation and the numbers on the other side of the equation. Essentially, if we subtract from both sides or add to both sides, it's exactly like moving a term to the other side!
If the number is next to $X$ with a plus, we will need to subtract it from both sides.
If the number is next to $X$ with a minus, we will need to add it to both sides.

For example:
$X+7=12$

Solution:
The goal is to leave only the $X$ on one side. This means we need to get rid of the $7$.
To get rid of it, we need to subtract $7$ from both sides. We get:
$x=5$

Another exercise:
$x-4+6=12$

Solution:
To isolate $X$, we need to add $4$ to both sides and subtract $6$ from both sides.
We get
$x=12+4-6$
$x=10$

Click here to read more about solving using addition or subtraction!

We will need to multiply or divide both sides of the equations where there is a coefficient for $X$.
First, we want to reach a situation where only the $X$ is on one side and all the numbers are on the other side. Then we want to reach a situation where $X$ has no coefficient.
When the coefficient is multiplied with $X$, we will need to divide the equation on both sides.
When the variable is in the numerator, we will need to multiply both sides to eliminate the fraction.

For example:
$2x+6=18$

Solution:
First, we will move all the numbers to one side, we need to subtract $6$ from both sides.
We get:
$2x=12$
Now, to leave $X$ without a coefficient, we need to divide both sides by the coefficient of $X$ - $2$.
We get:
$X=6$

Another exercise:
$\frac{x}{4}=5$

Solution:
To eliminate the fraction, we need to multiply both sides by $4$ to cancel the denominator.
We get:
$X=20$

Click here to read more about solving using multiplication or division!

In this solution, we need to move all the numbers with the variable to one side and all the numbers without the variable to the other side. Of course, we will act according to the addition and subtraction signs accordingly.
Remember – every expression that changes sides changes its sign.

For example:
$5x-3=2x+9$

Solution:
Move all the $X$s to the left side and all the numbers to the right side.
We get:
$5x-2x=9+3$
$3x=12$
Now divide both sides by $3$ and we get:
$x=4$

For more information on solving by combining like terms, click here!

The distributive law will help us eliminate parentheses and simplify multiplication into simple addition and subtraction exercises.
Let's recall the distributive law:
$a(b+c)=ab+ac$
And the expanded distributive law:
$(a+b)(c+d)=ac+ad+bc+bd$
In equations with a first degree and one variable, we can apply the distributive law.

For example:
$2(x+3)=14$

Solution:
According to the distributive law, we get:
$2x+6=14$
Rearranging the terms, we get:
$2x=8$
$x=4$

Click here for more information on solving equations using the commutative law!