Question 838488
Close but not quite right: 
The sum of the two sides is 3x^2+17x-2. But somehow your subtracted 3x^2+17x+2 from the perimeter. So the constant term should be 12 - (-2) = 14, not 12 - 2 = 10.<br>
P.S. In response to the questions in your "Thank you" note"<ul><li>Once again, the sum of the two angles is 3x^2+17x-2 <u>not</u> 3x^2+17x+2</li><li>Any time a subtraction is to be done, you have a choice of actually subtracting or adding the opposite. (For many reasons I highly recommend adding the opposite instead of subtracting.) So in this problem, you can either...<ul><li>Subtract:
(13x^2-14x+12) - (3x^2+17x-2)
which is difficult to get right; or...</li><li>Add the opposite:
(13x^2+(-14x)+12) + [-(3x^2+17x-2)]
which is the same as:
13x^2+(-14x)+12 + (-3x^2)+(-17x)+2
which is a lot easier to get right. (Note that the opposite of a polynomial has all of its signs changed.)</li></ul>Either way, done correctly gives the answer of: 10x^2-31x+14</li></ul>