[tex]a) (x + y + z) - ( -x + y +z) + (- x - y + z)[/tex][tex]=\ \textgreater \ x+y+z-(-x+y+z)-x-y+z=\ \textgreater \ z+x-y-z+z[/tex][tex]=\ \textgreater \ x-y+z[/tex]
[tex]b) 2x - ( - 3x - 1 + 2 x^{2} ) + 3 x^{2} + (- 2x + 1 - 3 x^{2} ) [/tex][tex]=\ \textgreater \ 2x-(-3x-1+2 x^{2} )+3 x^{2} -2x+1-3 x^{2} =\ \textgreater \ 3x+1-2 x^{2} +1[/tex][tex]=\ \textgreater \ 3x+2-2 x^{2} [/tex]
[tex]c)-( x^{2} -3 x^{2} -1)-6x-1-(3 x^{2} -1-3 x^{2} )[/tex][tex]=\ \textgreater \ -(-2 x^{2} -1)-6x-1-(-1)=\ \textgreater \ -(-2 x^{2} -1)-6x-1+1[/tex][tex]=\ \textgreater \ 2 x^{2} +1-6x[/tex]
[tex]Succes[/tex]