2x + 28 = 40
You are trying to isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Remember to follow PEMDAS. PEMDAS is the order of operations, and stands for:
Parenthesis
Exponents (& Roots)
Multiplications
Divisions
Additions
Subtractions
The first step in doing this is to subtract 28 from both sides:
2x + 28 (-28) = 40 (-28)
2x = 40 - 28
2x = 12
The second and last step is to divide 2 from both sides of the equation:
(2x)/2 = (12)/2
x = 12/2
x = 6
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