Respuesta :

[tex]15x-10x^{3}[/tex] has common factor [tex]5x[/tex]
which gives
[tex]5x(3-2x^{2})[/tex]

[tex]9x^{2}+3x^{3}[/tex] has common factor [tex]3x^{2}[/tex]
which gives
[tex]3x^{2}(3+x)[/tex]
You find the highest common factor, in the first one this is 5x
5x(3-2x^2)
For the second it's 3x
3x(3x+x^2)