\[\boxed{\text{714\ (714).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ 2a + ac^{2} - a^{2}c - 2c =\]
\[= (2a - 2c) - \left( a^{2}c - ac^{2} \right) =\]
\[= 2 \cdot (a - c) - ac(a - c) =\]
\[= (a - c)(2 - ac)\]
\[если\ a = 1\frac{1}{3} = \frac{4}{3};\ \]
\[c = - 1\frac{2}{3} = - \frac{5}{3}:\]
\[\left( \frac{4}{3} + \frac{5}{3} \right)\left( 2 + \frac{4}{3} \cdot \frac{5}{3} \right) =\]
\[= \frac{9}{3} \cdot \left( 2 + \frac{20}{9} \right) = 3 \cdot \left( 2 + \frac{20}{9} \right) =\]
\[= 3 \cdot 2 + 3 \cdot \frac{20}{9} = 6 + \frac{20}{3} =\]
\[= 6 + 6\frac{2}{3} = 12\frac{2}{3}.\]
\[\textbf{б)}\ x^{2}y - y + xy^{2} - x =\]
\[= ( - x - y) + \left( x^{2}y + xy^{2} \right) =\]
\[= - (x + y) + xy(x + y) =\]
\[= (x + y)(xy - 1)\]
\[если\ x = 4;\ \ y = 0,25:\]
\[(4 + 0,25)(4 \cdot 0,25 - 1) =\]
\[= 4,25 \cdot (1 - 1) = 4,25 \cdot 0 = 0.\]