173 Вправа 173Алгебра 8 клас Тарасенкова 2025 · § 4 · стор. 51

173. Виконайте дії:

1) ${\displaystyle \frac{3\cdot \left(x+3\right)-3x}{(x-4)(x+3)}=}$${\displaystyle \frac{3x+9-3x}{(x-4)(x+3)}=}$${\displaystyle \frac{9}{\left(x-4\right)\left(x+3\right)}}$;

2) ${\displaystyle x^2-3x-4=}$${\displaystyle x^2-4x+x-4=}$${\displaystyle (x+1)(x-4)}$;

${\displaystyle \frac{2\cdot \left(x-4\right)+(6-x)\cdot \left(x+1\right)-(7x-x^2)}{(x+1)(x-4)}=}$${\displaystyle \frac{2x-8+6x+6-x^2-x-7x+x^2}{(x+1)(x-4)}=}$${\displaystyle \frac{2x+6x-x-7x-x^2+x^2-8+6}{(x+1)(x-4)}=}$${\displaystyle -\frac{2}{\left(x+1\right)\left(x-4\right)}}$.