Question

Алгебра за 8 класс. Срочно

Answer 1

Объяснение:

1)

$\frac{y - 18}{ {6y}^{2} } - \frac{2 - 3y}{ {6y}^{3} } = \frac{y \times (y - 18) - 6 \times (2 - 3y)}{ {6y}^{3} } = \frac{ {y}^{2} - 18y - 12 + 18y }{ {6y}^{3} } = \frac{ {y}^{2} - 12 }{ {6y}^{3} }$

2)

$\frac{ {24x}^{2} }{6x - 3} - 4x = \frac{ {24x}^{2} - 4x \times (6x - 3)}{6x - 3} = \frac{ {24x}^{2} - {24x}^{2} + 12x}{6x - 3} = \frac{12x}{6x - 3} = \frac{12x}{3(2x - 1)} = \frac{4x}{2x - 1}$

3)

$\frac{b - 7}{b + 7} - \frac{ {b}^{2} + 49 }{ {b}^{2} + 14b + 49} = \frac{b - 7}{b + 7} - \frac{ {b}^{2} + 49 }{ {(b + 7)}^{2} } = \frac{(b + 7) \times (b - 7) - ( {b}^{2} + 49) }{ {(b + 7)}^{2} } = \frac{ {b}^{2} - 49 - {b}^{2} - 49}{ {(b + 7)}^{2} } = \frac{ - 98}{ {(b + 7)}^{2} } = - \frac{98}{ {(b + 7)}^{2} }$