Identify the monomial, binomial and trinomial from the following algebraic expression.
$-\mathrm{x}+\mathrm{y}-2\mathrm{z}$

Identify the monomial, binomial and trinomial from the following algebraic expression.

$71\mathrm{x}+75\mathrm{y}-15\mathrm{z}$

Arrange the terms of the following algebraic expression in the descending order of their powers.

$-2{\mathrm{x}}^2{\mathrm{y}}^2+3{\mathrm{x}}^3{\mathrm{y}}^2+5\mathrm{xy}-4{\mathrm{x}}^3{\mathrm{y}}^3$