The area of rectangular envelope is given by the trinomial x^2 +8x+7. the length of the envelope is x+7. what is the width of the envelope ?

X+1 is the width of the envelope. If you need work just say do in the comments please.

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.