Решебник по алгебре 7 класс Мерзляк ФГОС Задание 857

 

\[\boxed{\text{857\ (857).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[1)\ y(10) = 1,2 \cdot 10 = 12\ \ \]

\[y(0,6) = 1,2 \cdot 0,6 = 0,72\]

\[y( - 5) = 1,2 \cdot ( - 5) = - 6\]

\[y( - 4) = 1,2 \cdot ( - 4) = - 4,8.\]

\[2)\ при\ y = 3,6:\ \ \]

\[1,2x = 3,6\ \ \]

\[x = 3.\]

\[при\ y = - 2,4:\ \ \]

\[1,2x = - 2,4\]

\[x = - 2.\]

\[при\ y = 6:\ \ \]

\[1,2x = 6\ \ \]

\[x = 5.\]

\[\boxed{\text{857.\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[1)\ 15\text{cx} + 2\text{cy} - \text{cxy} - 30c =\]

\[= 15c(x - 2) - \text{cy}(x - 2) =\]

\[= (x - 2)\left( 15c - \text{cy} \right) =\]

\[= c \cdot (15 - y)(x - 2)\]

\[2)\ 35a² - 42ab + 10a^{2}b - 12ab^{2} =\]

\[= 5a^{2}(7 + 2b) - 6ab(7 + 2b) =\]

\[= (7 + 2b)\left( 5a^{2} - 6ab \right) =\]

\[= a \cdot (7 + 2b)(5a - 6b)\]

\[3)\ x^{3} + x^{2}y + x^{2} + xy =\]

\[= x^{2}(x + y) + x(x + y) =\]

\[= (x + y)\left( x^{2} + x \right) =\]

\[= x \cdot (x + y)(x + 1)\]

\[4)\ mn^{4} - n^{4} + mn^{3} - n^{3} =\]

\[= n^{4}(m - 1) + n^{3}(m - 1) =\]

\[= (m - 1)\left( n^{4} + n^{3} \right) =\]

\[= n^{3}(m - 1)(n + 1)\]