Question

помогите плизз прошу​

Answer 1

1)

$\frac{a-\frac{a^2}{a+1} }{a-\frac{a}{a+1} } =\frac{\frac{a\cdot (a+1)-a^2}{a+1} }{\frac{a\cdot (a+1)-a}{a+1} } =\frac{\frac{a^2+a-a^2}{a+1} }{\frac{a^2+a-a}{a+1} } =\frac{\frac{a}{a+1} }{\frac{a^2}{a+1} } =\frac{a}{a+1} :\frac{a^2}{a+1} =\frac{a}{a+1} \cdot \frac{a+1}{a^2} =\frac{1}{a}$

2)

$\frac{a-\frac{6a-9}{a} }{1-\frac{3}{a} } =\frac{\frac{a\cdot a-(6a-9)}{a} }{\frac{a-3}{a} } =\frac{\frac{a^2-6a+9}{a} }{\frac{a-3}{a} } =\frac{\frac{(a-3)^2}{a} }{\frac{a-3}{a} } =\frac{(a-3)^2}{a} :\frac{a-3}{a} =\frac{(a-3)^2}{a} \cdot \frac{a}{a-3} =a-3$

3) условие неполное, не пропечатан знаменатель последней дроби:

$\frac{1}{1-\frac{1}{1+\frac{1}{?} } }$

4)

$\frac{\frac{2a-b}{b}+1 }{\frac{2a+b}{b}-1 }+\frac{3-\frac{b}{a} }{\frac{3a}{b}-1 }= \frac{\frac{2a-b+b}{b} }{\frac{2a+b-b}{b} }+\frac{\frac{3a-b}{a} }{\frac{3a-b}{b} }=\frac{\frac{2a}{b} }{\frac{2a}{b} }+\frac{\frac{3a-b}{a} }{\frac{3a-b}{b} }=1+\frac{3a-b}{a} :\frac{3a-b}{b}=1+\frac{3a-b}{a} \cdot \frac{b}{3a-b}=\\\\=1+\frac{b}{a} =\frac{a+b}{a}$