Question

Решите примеры отмеченные галочками.
Очень нужно. Даю 70 баллов​

Answer 1

Ответ:

$( \frac{x {}^{3} - 8 }{x - 2} + 2x) \div \frac{x {}^{2} + 4x + 4}{2 - x} = 2 - x$

$( \frac{m}{n {}^{2} - mn } + \frac{n}{m {}^{2} - mn } ) \times \frac{mn}{n + m} = - 1$

$( \frac{st}{s {}^{2} - t {}^{2} } + \frac{t}{2t - 2s} ) \times \frac{s + t}{2t} = \frac{1}{4}$

$\frac{ \frac{1}{x + y } + \frac{1}{x - y} }{ \frac{1}{x + y} - \frac{1}{x - y} } = - \frac{x}{y} = - \frac{x}{y}$

Answer 2

Ответ:

Объяснение:

4.5. ((1+с³)/(1+c) -c)(1+c)/(1-c²)=((1+c)(1-c+c²)-с(1+c))/(1+c) ·(1+c)/((1-c)(1+c))=((1+c)(1-c+c²-c))/((1-c)(1+c))=(1-2c+c²)/(1-c)=(1-c)²/(1-c)=1-c

((x³-8)/(x-2) +2x) ÷(x²+4x+4)/(2-x)=((x-2)(x²+2x+4)+2x(x-2))/(x-2) ·(-(x-2)/(x+2)²)=((x-2)(x²+2x+4+2x))/(-(x+2)²)=((x-2)(x+2)²)/(-(x+2)²)=-(x-2)=2-x

4.6. (m/(n²-mn) +n/(m²-mn))(mn)/(n+m)=(m/(n(n-m)) +n/(m(m-n)))(mn)/(n+m)=(-m²+n²)/(mn(m-n)) ·(mn)/(n+m)=((n-m)(n+m))/((m-n)(n+m))=-(m-n)/(m-n)=-1

((st)/(s²-t²) +t/(2t-2s))(s+t)/(2t)=((st)/((s-t)(s+t)) +t/(2(t-s)))(s+t)/(2t)=(2st-t(s+t))/(2(s-t)(s+t)) ·(s+t)/(2t)=(2st-st-t²)/(4t(s-t))=(t(s-t))/(4t(s-t))=1/4=0,25

4.7. m=3/14

((2m+1)/(2m-1) -(2m-1)/(2m+1)) ÷(4m)/(10m-5)=((2m+1)²-(2m-1)²)/((2m-1)(2m+1)) ·(5(2m-1))/(4m)=(5(2m+1-2m+1)(2m+1+2m-1))/(4m(2m+1))=(5·2·4m)/(4m(2m+1))=10/(2m+1)=10/(2·3/14 +1)=10/(3/7 +7/7)=10·7/10=7

4.8. (1/(x+y) +1/(x-y))/(1/(x+y) -1/(x-y))=-x/y

(x-y+x+y)/((x+y)(x-y)) ·((x+y)(x-y))/(x-y-x-y)=-x/y

(2x)/(-2y)=-x/y

-x/y=-x/y