Ответ: UWU

Объяснение:

1)

[tex]\frac{3a-7b}{5a-b}-\frac{42a-2b}{b-5a}= \frac{3a-7b}{5a-b}-\frac{42a-2b}{-(5a-b)}=\frac{3a-7b}{5a-b}+\frac{42a-2b}{5a-b}=\frac{3a-7b+42a-2b}{5a-b}=\frac{45a-9b}{5a-b}=\frac{9(5a-b)}{5a-b}=9[/tex]

2)

[tex]\frac{m^2}{2m-6}+\frac{9}{6-2m}=\frac{m^2}{2m-6}-\frac{9}{2m-6}= \frac{m^2-9}{2m-6}= \frac{(m-3)(m+3)}{2(m-3)}=\frac{m+3}{2}[/tex]

3)

[tex]\frac{p^2}{p^2-1}+\frac{2p-1}{1-p^2} =\frac{p^2}{p^2-1}+\frac{-(2p-1)}{p^2-1} =\frac{p^2-2p+1}{p^2-1} =\frac{(p-1)(p-1)}{(p-1)(p+1)}=\frac{p-1}{p+1}[/tex]

4)

[tex]\frac{3a-5}{(a-2)^2}+\frac{a-3}{(2-a)^2}= \frac{3a-5}{a^2-4a+4}+\frac{a-3}{4-4a+a^2} =\frac{3a-5+a-3}{a^2-4a+4}= \frac{4a-8}{(a-2)^2}=\frac{4(a-2)}{(a-2)^2}=\frac{4}{a-2}[/tex]

в общем, использованные формулы

[tex]+\frac{-x}{y} =+\frac{x}{-y}=-\frac{x}{y}[/tex]

a(b+c)=ab+ac

[tex]a^2+2ab+b^2=(a+b)^2\\a^2-2ab+b^2=(a-b)^2[/tex]

[tex](a)^2=(-a)^2=a*a=(-a)*(-a)[/tex]

[tex]a^2-b^2=(a-b)(a+b)[/tex]