Here are the polynomials written in simple form with respect to x:
11. 7y+4x+2
12. 2x-3y2 +y
13. 7ax-5x +7x = 9x-5x = 4x
14. 7xy - 9xy - 3xy2- 4 = -2xy -3xy2 - 4
15. 7ay - 5x + 7x = 2x + 7ay
16. 2x - 3y - 2y2 - 1= -1 -3y- 2y2 +2x
17. 4a2b + 3ab2 - 2ab -1 = -1 - 2ab + 3ab2 + 4a2b
18. 7xy- 9xy - 3xy2 -4 = -2xy - 3xy2 -4