Grade 6 → Algebra → Solving Simple Equations ↓
Solving Two-Step Equations
In algebra, you will often come across equations that require more than one step to solve. These are known as two-step equations. This means that you have to perform two operations to find the value of the variable. Let's take a deeper look at how to solve two-step equations in a simple and easy to understand way.
Understanding the basics
Before we begin solving two-step equations, let's first remember what an equation is. An equation is a mathematical statement that shows that two expressions are equal. It often includes a variable, such as x
or y
, which represents an unknown number you need to find.
A basic equation looks like this:
x + 5 = 12
Here, x
is our variable, and we need to find the value of x
that makes both sides of the equation equal. This example is a one-step equation because you can solve it by performing a single operation: subtracting 5 from both sides.
In contrast, a two-step equation might look like this:
2x + 3 = 11
Here, you need to perform two operations to isolate x
and find its value.
Steps to solve two-step equations
Let's understand the process of solving a two-step equation. We will follow these general steps:
- Identify operations that affect the variable. Identify combined operations with variables on the same side of the equation.
- Undo the addition or subtraction. Use the inverse operation to remove the constant term on the variable side.
- Undo the multiplication or division. Use the inverse operation to solve for the variable.
Let's use these steps to solve our example equation:
Example 1: Solving 2x + 3 = 11
Step 1: Identify the operations affecting x
In 2x + 3 = 11
, the variable x
is being multiplied by 2, and then 3 is being added. We will reverse these operations.
Step 2: Undo the addition
Subtract 3 from both sides of the equation to remove +3
:
2x + 3 - 3 = 11 - 3
The simplification of which is as follows:
2x = 8
Step 3: Undo the multiplication
To solve for x
, divide both sides by 2:
2x / 2 = 8 / 2
From this we get:
x = 4
So, the solution of the equation 2x + 3 = 11
is x = 4
.
Let’s look at another example!
For better understanding consider the equation:
3x - 4 = 5
Step 1: Identify the operations affecting x
The variable x
is multiplied by 3, and 4 is subtracted. We will reverse these operations.
Step 2: Undo the subtraction
Add 4 to both sides to cancel the subtraction:
3x - 4 + 4 = 5 + 4
The simplification of which is as follows:
3x = 9
Step 3: Undo the multiplication
Divide both sides by 3:
3x / 3 = 9 / 3
From this we get:
x = 3
Therefore, the solution of the equation 3x - 4 = 5
is x = 3
.
More practice problems
Let's practice solving two-step equations using the steps we just learned. This will strengthen your understanding.
Example 2: 5x + 7 = 22
Step 1: Identify the operations affecting x
.
In 5x + 7 = 22
, x
is multiplied by 5, and then 7 is added.
Step 2: Undo the sum by subtracting 7 from both sides:
5x + 7 - 7 = 22 - 7
Simplification:
5x = 15
Step 3: Undo the multiplication by dividing both sides by 5:
5x / 5 = 15 / 5
which gives:
x = 3
Example 3: 4x - 10 = 6
Step 1: Identify the operations affecting x
.
Here, x
is multiplied by 4, and 10 is subtracted.
Step 2: Undo the subtraction by adding 10 to both sides:
4x - 10 + 10 = 6 + 10
Simplification:
4x = 16
Step 3: Undo the multiplication by dividing both sides by 4:
4x / 4 = 16 / 4
this results in:
x = 4
Key points to remember
- Always do the opposite operation to isolate the variable.
- Balance the equation by performing the same operation on both sides.
- Check your solution by substituting it back into the original equation to make sure it makes both sides equal.
Conclusion
Solving two-step equations is a foundational skill in algebra that develops logical thinking and problem-solving abilities. By mastering the process of identifying operations and applying inverse operations step-by-step, you can solve these equations with confidence. Remember, constant practice is key to understanding and becoming proficient at two-step equations. Keep practicing different problems to further enhance your skills!