a)
[tex] \frac{1}{2} (x + 7y - 3z) = \frac{1}{2} x + \frac{7}{2} y - \frac{3}{2} z[/tex]
b)
[tex] {x}^{2} + 5x + 1 - {x}^{2} - 6x + 2 = - x + 3[/tex]
c)
[tex] - 5x(x + 2y) = - 5 {x}^{2} - 10xy[/tex]
d)
[tex]3xy + 2 {x}^{2} y - 3yx + {xy}^{2} = 3xy + 2 {x}^{2} y - 3yx + {xy}^{2} [/tex]
[tex] \huge{ \boxed{Odp.C}}[/tex]
