Решите пожалуйста все, без ошибок желательно (Решающая к.р.

1) $\frac{-8}{-2+0,3}$ = 4,7

2) $\frac{3a^4b^3}{15a^5b} = \frac{b^2}{5a}$

3) $x - \frac{x^2+y^2}{x+y} = \frac{x(x+y)}{x+y} - \frac{x^2+y^2}{x+y} = \frac{x(x+y)-x^2+y^2}{x+y} = \frac{xy + y^2}{x+y} = \frac{y(x+y)}{x+y} = y$

4) $\frac{10a}{a-b} * \frac{a^2-b^2}{5a} = 2a + 2b$

5) $\frac{7,5*10^{-7}}{5*10^{-4}} = \frac{7,5 * 0,001}{5} = 0,0015$
   $\frac{7,5*10^{-7}}{5*10^{-4}} \ \textless \ 0,015$

6) $\frac{4x}{10} - \frac{5(x-3)}{10} - \frac{10}{10} = 0$
   $\frac{4x-5(x-3)-10}{10} = 0$
4x - 5x + 15 - 10 = 0
-x + 5 = 0
-x = -5
x = 5

7) $\frac{x}{24} = \frac{x}{15} - 150$
   $\frac{5x}{120} - \frac{8x}{120} + 150 = 0$
   $- \frac{x}{40} + 150 = 0$
   $- \frac{x}{40} = -150$
   $150 = \frac{x}{40}$
   $x= 150 * 40$
x = 6000

8) $\frac{m^2-n^2-km+kn}{k^2-km-mn-n^2} = \frac{(m+n)(m-n)-k(m-n)}{(k+n)(k-n)-m(k+n)} = \frac{(m+n-k)(m-n)}{(k-n-m)(k+n)}$

9) $\frac{3+4x}{2} + \frac{12}{2} = \frac{2x-3}{2y} - \frac{1-5x}{7}$
$\frac{7(3+4x)}{14} + \frac{84}{14} - \frac{7(2x-3)}{14} - \frac{2(1-5x)}{14} = 0$
7(3 + 4x) + 84 - 7(2x - 3) - 2(1 - 5x) = 0
21 + 28x + 84 - 14x + 21 - 2 + 10x = 0
24x = -124
x = - 5,1(6)