Grade 7 → Algebra → Linear Equations ↓
Solving Simple Equations
Linear equations are mathematical statements of equality involving constants and variables. In grade 7 math, solving simple linear equations involves finding the value of the variable that makes the equation true. We will explore this concept using text explanations, examples, and visual illustrations.
Understanding linear equations
A simple linear equation in algebra is usually written in the form:
ax + b = c
In this form:
a
,b
andc
are constants (known numbers).x
is the variable (the unknown number we need to find).
Our goal when solving these equations is to determine the value of the variable (x
) by isolating it on one side of the equation.
Basic steps to solve simple equations
Simple steps can be followed to solve simple linear equations. Let us see these steps used to solve the equation step by step.
Example 1: Solving x + 5 = 12
Step 1: Identify what is on both sides of the equation. Our equation is:
x + 5 = 12
Step 2: The goal is to get x
alone on one side of the equation. We do this by cancelling out the constant on the side with the variable. Here, we need to remove +5
.
Step 3: Use the inverse operation. The inverse of addition is subtraction. So, subtract 5
from both sides.
(x + 5) - 5 = 12 - 5
By simplification we get:
x = 7
This means that when x
is 7
, the equation x + 5 = 12
is true. We can check this by substituting 7
back into the equation:
7 + 5 = 12
So, 12 = 12
, which confirms that our solution is correct.
Example 2: Visual example of solving 2x = 10
The rectangles given above have 2x
written on one side and 10
on the other. To solve 2x = 10
, we have to find the value of x
.
Step 1: Divide both sides by 2 (the inverse of multiplying by 2).
(2x)/2 = 10/2
Step 2: Simplify both sides:
x = 5
Therefore, the solution of the equation is x = 5
.
More text examples with step-by-step explanations
Example 3: Solving 3x - 4 = 11
This equation involves subtraction operation.
Step 1: Solve the subtraction problem by adding 4
to both sides of the equation.
3x - 4 + 4 = 11 + 4
This makes it simpler:
3x = 15
Step 2: Now, to isolate x
, divide both sides by 3
.
(3x)/3 = 15/3
By simplification we get:
x = 5
Check: Substitute 5
into the original equation:
3(5) - 4 = 11
Simplifying, 15 - 4 = 11
, which is correct.
Example 4: Solving 4 + x = 20
Step 1: We need to isolate x
by cancelling out the constant. Subtract 4
from both sides.
4 + x - 4 = 20 - 4
Simplifying both sides, we get:
x = 16
Check: Substitute 16
into the original equation:
4 + 16 = 20
Simplifying, 20 = 20
, which is correct.
Summary
Solving simple equations involves a few essential steps: understanding the structure of the equation, performing inverse operations to isolate the variable, and then simplifying to find the value of the unknown. Practice is key to becoming proficient at solving equations, and visualizing the balance between the two sides can help understand the process.
Remember, the concept of balancing an equation is like a scale, where the goal is to keep both sides equal, while performing operations to isolate and determine the unknown variable.