Answer:
1.a²+25
2.9x²y²-49
3.x+y-2 (sorry kung mali di ko maintindihan)
4.4x²+9y²+25
5.9a²-b²+4c²
6.-(4x²-8)
7.9x²y²-a²b²c²
8.x⁴-4y⁴
9.x²+3
10.x²-y²+6x-3y+9
11.(2+2x) di ko maintindihan sorry
12.x²-3
13.8x³+125
14.[(x+1)-y (mali ata type)
15.x+y³-8 ._.