11p+11
minus 4 plus 9 = 5, so 5x
4y -5
9
7(3y-2)-(-4y+9)
4p + 9 - 7p + 2 4p - 7p + 9 + 2 p(4 - 7) + 9 + 2 -3p + 11
i dont no
If you mean the roman numerals, then IX = 9 and XI = 11, and 11+9=20 which can be written as XX.
9x + 91 is already simplified because there is nothing that is on the other side of the "equals" sign.
6x + 9 + 2x = 8x + 9
IX (9) + XV (15) + XX (20) = XLIV (44)
9 plus 87 equals 96.