Gr8fu13 said:
The problem is:
(-2b^2+8b+2)-(9b^2+2)
I changed the sign of the second part of the equation to:
(-2b^2+8b+2)+(-9b^2-2)
I combined like terms:
(-2-9)b^2+8b+(2-2)
I came up with answer as:
-11b^2+8b
Is this correct? If not, please show me where I messed up. Thanks!
Your work/answer are correct. It is better to space appropriate characters
apart, such as addition and subtraction signs, for easier readability.
Also, note
http://math.about.com/library/blpoly.htm in the "subtracting polynomials" section.
When the instructions are to "subtract the polynomials,"
then the resulting polynomial is not to be factored. That is standard operating procedure.
If the instructor wants that result to be additionally factored, then that must be stated.
As you stated, you were not told to "simplify." However, part of subtracting the polynomials
and presenting the final answer includes adding together all the like terms.
Quote Gr8fu13 Subtracting polynomials
by Gr8fu13 » Thu Mar 24, 2011 6:59 pm
The problem is:
\(\displaystyle (-2b^2 + 8b + 2) - (9b^2 + 2)\)
I changed the sign of the second part of the equation to:
\(\displaystyle (-2b^2 + 8b + 2) + (-9b^2 - 2) \ **\)
I combined like terms:
\(\displaystyle (-2 - 9)b^2 + 8b + (2 - 2)\)
I came up with answer as:
\(\displaystyle -11b^2 + 8b\)
-----------------------------------------------------------------------
\(\displaystyle ** \ \text{I \ might show \ these \ instead \ as:}\)
\(\displaystyle -2b^2 + 8b + 2 - 9b^2 - 2 \ = \\)
\(\displaystyle -2b^2 - 9b^2 + 8b + 2 - 2 \ =\\)
\(\displaystyle \boxed{-11b^2 + 8b}\)
