Solving an equation in one variable

Algebra 1 Tutorial

Solving an equation in one variable

Intro

In general, a one-variable equation such as ax+b=c can be solved by “undoing” the order of operations (PEMDAS).
The order of operations is: parenthesis, exponents, multiplication, division, addition, subtraction. By doing the order of operations in reverse, we unravel the equation and isolate the variable.

Sample Problem

Solve for x:

4x+4=20

20


-4


4


8


2


Solution

Here is the systematic way to solve this equation:

Subtract 4 from both sides.

4x+4=20
    -4  -4
___________
4x   =16

Divide both sides by 4.

4x=16
 /4  /4

x=4



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