Вычислите: 1) \(\frac{5}{7}-\frac{2+x}{7}=\frac{5-(2+x)}{7}=\frac{3-x}{7}\); 2) \(\frac{2}{3}-\frac{1-x}{3}\); 3) \(\frac{x}{2}-\frac{2x+3}{2}\); 4) \(\frac{a}{5}-\frac{9-a}{5}\); 5) \(\frac{b}{y^2}-\frac{b-a}{y^2}\); 6) \(\frac{a}{2x}-\frac{a+b}{2x}\); 7) \(\frac{m}{6x}-\frac{m+a}{6x}\); 8) \(\frac{2a}{11b}-\frac{a+2}{11b}\); 9) \(\frac{2}{3a}-\frac{3b+4}{3a}\); 10) \(\frac{x+2}{3y}-\frac{2x+5}{3y}\); 11) \(\frac{a-7}{a^2}-\frac{15+2a}{a^2}\); 12) \(\frac{x+1}{2y}-\frac{3x-6}{2y}\); 13) \(\frac{5x-2y}{a}-\frac{3x+y}{a}\); 14) \(\frac{12a+5b}{3b}-\frac{2a-b}{3b}\); 15) \(\frac{14m-n}{xy}-\frac{2n-3m}{xy}\); 16) \(\frac{3a^3+x}{4a}-\frac{5x-2a^3}{4a}\).

У дробей с одинаковыми знаменателями вычитаем числители, сохраняя знаменатель. В примере 1 числитель уже преобразован: \(5-(2+x)=3-x\).

1. \(\frac{3-x}{7}\).
2. \(\frac{2-(1-x)}{3}=\frac{1+x}{3}\).
3. \(\frac{x-(2x+3)}{2}=\frac{-x-3}{2}\).
4. \(\frac{a-(9-a)}{5}=\frac{2a-9}{5}\).
5. \(\frac{b-(b-a)}{y^2}=\frac{a}{y^2}\).
6. \(\frac{a-(a+b)}{2x}=-\frac{b}{2x}\).
7. \(\frac{m-(m+a)}{6x}=-\frac{a}{6x}\).
8. \(\frac{2a-(a+2)}{11b}=\frac{a-2}{11b}\).
9. \(\frac{2-(3b+4)}{3a}=-\frac{3b+2}{3a}\).
10. \(\frac{(x+2)-(2x+5)}{3y}=-\frac{x+3}{3y}\).
11. \(\frac{(a-7)-(15+2a)}{a^2}=-\frac{a+22}{a^2}\).
12. \(\frac{(x+1)-(3x-6)}{2y}=\frac{7-2x}{2y}\).
13. \(\frac{(5x-2y)-(3x+y)}{a}=\frac{2x-3y}{a}\).
14. \(\frac{(12a+5b)-(2a-b)}{3b}=\frac{10a+6b}{3b}\).
15. \(\frac{(14m-n)-(2n-3m)}{xy}=\frac{17m-3n}{xy}\).
16. \(\frac{(3a^3+x)-(5x-2a^3)}{4a}=\frac{5a^3-4x}{4a}\).