find the sum/difference of the following polynomial expressions if anyone answer this correctly ill give it the brainliest

1.3x+10x

2.12y-18y

[tex]3.14x^{2} +(-16x^{3})[/tex]

[tex]4.-5x^{3}-4x^{3}[/tex]

5.2x-3x

6.10xy-8xy

[tex]7.20x^{2} y^{2}+30x^{2} y^{2}[/tex]

[tex]8.-9x^{2} y+9x^{2} y[/tex]

[tex]9.-10x^{2} y^{3}-10x^{2} y^{3}[/tex]

10.5x-3x-8x+6x