Question

помогите, с решением пожалуйста

Answer 1

а)

$\frac{3x + y}{3x} + \frac{x - 2y}{6x} = \frac{2(3x + y) + x - 2y)}{6x} = \\ = \frac{6x + 2y + x - 2y}{6x} = \frac{7x}{6x} = \frac{7}{6} = 1 \frac{1}{6}$

б)

$\frac{2}{c} - \frac{c}{c - 5} = \frac{2(c - 5) - c \times c}{c(c - 5)} = \frac{ - {c}^{2} + 2c - 10}{c {}^{2} - 5c}$

в)

$\frac{a + 4}{a - 1 } - \frac{a - 3}{a + 2} = \frac{(a + 4)(a + 2) - (a - 3)(a - 1)}{(a - 1)(a + 2)} = \\ = \frac{ {a}^{2} + 2a + 4a + 8 - {a}^{2} + a + 3a - 3}{ {a }^{2} + 2a - a - 2 } = \\ = \frac{10a + 5}{a {}^{2} + a - 2 }$

г)

$\frac{3y}{ {y}^{2} - 14y + 49} + \frac{3}{y - 7} = \frac{3y}{(y - 7) {}^{2} } + \frac{3}{y - 7} = \\ = \frac{3y + 3(y - 7)}{(y - 7) {}^{2} } = \frac{3y + 3y - 21}{(y - 7) {}^{2} } = \frac{6y - 21}{ {y}^{2} - 14y + 49 }$

д)

$\frac{2b}{ {b}^{2} - {c}^{2} } - \frac{2}{b + c} = \frac{2b}{(b - c)( b + c)} - \frac{2}{b + c} = \\ = \frac{2b - 2(b - c)}{(b - c)(b + c)} = \frac{2b - 2b + 2c}{ {b}^{2} - {c}^{2} } = \frac{2c}{ {b}^{2} - {c}^{2} }$