Solving Basic Equations (Jump to: Lecture | Video )

Let's start with a simple identity:

4 = 4

If we apply the same operations to both sides of the equation, the quantities will remain equal to each other. For example, let's multiply each side by 2:

8 = 8

Now, we can subtract 7 from each side:

1 = 1

Because we applied the same operation to both sides, the equation remained true. Let's try to use this information to solve for a variable:

2x + 8 = 12

What is x? First, we want to get x alone on the left side. Let's start by subtracting 8 from both sides:

2x = 4

Now, let's divide both sides by 2 to get x all alone:

x = 2

Our final answer is x = 2. Is this the correct answer? Check by substituting it into the original equation.