When adding or subtracting polynomials in parentheses
such as (...........) + (.........), do the exponents of common factors stay the same or change? What about multiplying?
You can add 4x to 8x because 4x is 4 x’sand 8x is 8x’s,
which is 4x’s + 8x’s to get 12 x’s or 12x. But why can't you add 4x2+ 2x? I don't understand why you can't add a squared variable to the same letter that isn't squared. 
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