№2 Найдите значение выражения a) $$-x^5$$, $$x = -2$$; б) $$2x^2y^2$$, $$x = -0{,}5$$, $$y = -2$$; в) $$-200xy$$, $$x = -\frac{1}{2}$$, $$y = -0{,}1$$; г) $$-12c^3$$, $$c = -\frac{1}{2}$$; д) $$3 - x^3$$, $$x = -1$$; е) $$5xy^2$$, $$x = -1$$, $$y = 2$$.

a) $$-x^5, x = -2$$ $$ -(-2)^5 = -(-32) = 32 $$

б) $$2x^2y^2, x = -0{,}5, y = -2$$ $$2 \cdot (-0{,}5)^2 \cdot (-2)^2 = 2 \cdot 0{,}25 \cdot 4 = 2$$

в) $$-200xy, x = -\frac{1}{2}, y = -0{,}1$$ $$-200 \cdot (-\frac{1}{2}) \cdot (-0{,}1) = -10$$

г) $$-12c^3, c = -\frac{1}{2}$$ $$-12 \cdot (-\frac{1}{2})^3 = -12 \cdot (-\frac{1}{8}) = \frac{12}{8} = \frac{3}{2} = 1{,}5$$

д) $$3 - x^3, x = -1$$ $$3 - (-1)^3 = 3 - (-1) = 3 + 1 = 4$$

е) $$5xy^2, x = -1, y = 2$$ $$5 \cdot (-1) \cdot 2^2 = 5 \cdot (-1) \cdot 4 = -20$$