We know that the equation is a true equation for a particular value of x.
Now, let's see what happens if we divide everything by 4. In other words:
Divide:
So, we get .
When we divided everything by 4, we used the division property of equality. Under this property, the equation remains the same even if we divided since we did the <em>same thing to both sides of the equation. </em>
Therefore, is also true for the same value of x because it is just a simplified version of .