Answer:
x = 5
Step-by-step explanation:
Simplify. First, combine like terms: 
3x - x + 2 = 12
(3x - x) + 2 = 12
(2x) + 2 = 12
2x + 2 = 12
Isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS. 
PEMDAS = 
Parenthesis
Exponents (& Roots)
Multiplication
Division
Addition
Subtraction
& is your order of operation. 
First, subtract 2 from both sides: 
2x + 2 (-2) = 12 (-2)
2x = 12 - 2
2x = 10
Next, divide 2 from both sides: 
(2x)/2 = (10)/2
x = 10/2
x = 5
5 is your answer for x. 
Check: Plug in 5 for x in the equation. Solve: 
3(5) - (5) + 2 = 12
15 - 5 + 2 = 12
10 + 2 = 12
12 = 12 (True)
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