Решебник по алгебре 7 класс Макарычев ФГОС Задание 674

 

\[\boxed{\text{674.}\text{\ }еуроки - ответы\ на\ пятёрку}\]

Пояснение.

Решение.

\[\textbf{а)}\ a² + a = a(a + 1)\]

\[\textbf{б)}\ x³ - x^{2} = x²(x - 1)\]

\[\textbf{в)}\ c^{5} + c^{7} = c^{5}(1 + c^{2})\]

\[\textbf{г)}\ a³ - a^{7} = a³(1 - a^{4})\]

\[\textbf{д)}\ 3m² + 9m³ = 3m²(1 + 3m)\]

\[\textbf{е)}\ 9p³ - 8p = p(9p^{2} - 8)\]

\[\textbf{ж)}\ 4c² - 12c^{4} = 4c²(1 - 3c^{2})\]

\[\textbf{з)}\ 5x^{5} - 15x^{3} = 5x³(x^{2} - 3)\]

\[\textbf{и)} - 12y^{4} - 16y =\]

\[= - 4y \cdot (3y^{3} + 4)\]

\[\boxed{\text{674\ (674).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)}\ \frac{3x - 5}{2} + \frac{8x - 12}{7} = 9\ \ \ | \cdot 14\]

\[7 \cdot (3x - 5) + 2 \cdot (8x - 12) =\]

\[= 9 \cdot 14\]

\[21x - 35 + 16x - 24 = 126\]

\[37x = 126 + 59\]

\[37x = 185\]

\[x = 5\]

\[Ответ:x = 5.\]

\[\textbf{б)}\ \frac{21 - 4x}{9} - \frac{8x + 15}{3} = 2\ \ \ | \cdot 9\]

\[21 - 4x - 3 \cdot (8x + 15) = 18\]

\[21 - 4x - 24x - 45 = 18\]

\[- 28x = 18 + 24\]

\[- 28x = 42\]

\[x = 42\ :( - 28) = - \frac{42}{28} = - \frac{3}{2}\]

\[x = - 1,5\ \]

\[Ответ:x = - 1,5.\]