Pre Algebra
posted by Lily .
the problem is about adding and subtracting polynomials...
This is what I did...
2x+3+3x+1
=2x+3x+3+1
=5x+4
and
9x+115x+4
=9x5x+11+4
=4x+15
but then, if I add both 5x+4+4x+15
=9x+19...

I think this deals with the same problem you posted at 8:49 pm
In this question I think you wanted to subract 5x+4 from 9x+11
that would be 9x+11  (5x+4)
= 9x + 11  5x  4
= 4x + 7
See how important brackets and the order of operations are ??