Применены формулы взаимозависимости работы, времени и производительности
Ответ:
2а
1.8/0.5*2.4=1.8/1.2=1.5
2в
12-1/4*(-2)5=12-1/4*(-32)=12-1 * (-32)сокращаем = 12-1*(-8)=12-(-8)=20
4 1
5
СА
68+63+73+67+75= 346/5=69.2
рз
75-63=12
6
-3.2/0.16=-200
7
(-1.6)6 (-1.6) (-1.6)3
Объяснение:
Избавление от рациональности в знаменателе "лечится" умножением числителя и знаменателя на выражение, сопряжённое со знаменателем.
1)
![\frac{x-1}{ \sqrt{x+3}-2}](https://tex.z-dn.net/?f=+%5Cfrac%7Bx-1%7D%7B+%5Csqrt%7Bx%2B3%7D-2%7D+)
умножаем числитель и знаменатель на
![\sqrt{x+3}+2](https://tex.z-dn.net/?f=%5Csqrt%7Bx%2B3%7D%2B2)
![\frac{x-1}{ \sqrt{x+3}-2}=\frac{(x-1)*(\sqrt{x+3}+2)}{(\sqrt{x+3}-2)*(\sqrt{x+3}+2)}=\frac{(x-1)*(\sqrt{x+3}+2)}{x+3-4}=\sqrt{x+3}+2](https://tex.z-dn.net/?f=%5Cfrac%7Bx-1%7D%7B+%5Csqrt%7Bx%2B3%7D-2%7D%3D%5Cfrac%7B%28x-1%29%2A%28%5Csqrt%7Bx%2B3%7D%2B2%29%7D%7B%28%5Csqrt%7Bx%2B3%7D-2%29%2A%28%5Csqrt%7Bx%2B3%7D%2B2%29%7D%3D%5Cfrac%7B%28x-1%29%2A%28%5Csqrt%7Bx%2B3%7D%2B2%29%7D%7Bx%2B3-4%7D%3D%5Csqrt%7Bx%2B3%7D%2B2)
2)
![\frac{ x^{2} -2x}{ \sqrt{x+2}-2}](https://tex.z-dn.net/?f=+%5Cfrac%7B+x%5E%7B2%7D+-2x%7D%7B+%5Csqrt%7Bx%2B2%7D-2%7D+)
умножаем числитель и знаменатель
![\sqrt{x+2}+2](https://tex.z-dn.net/?f=%5Csqrt%7Bx%2B2%7D%2B2)
![\frac{ x^{2} -2x}{ \sqrt{x+2}-2}= \frac{ (x^{2} -2x)*(\sqrt{x+2}+2)}{ (\sqrt{x+2}-2)*(\sqrt{x+2}+2)}=\frac{ x*(x -2)*(\sqrt{x+2}+2)}{ x+2-4}=x*(\sqrt{x+2}+2)](https://tex.z-dn.net/?f=+%5Cfrac%7B+x%5E%7B2%7D+-2x%7D%7B+%5Csqrt%7Bx%2B2%7D-2%7D%3D+%5Cfrac%7B+%28x%5E%7B2%7D+-2x%29%2A%28%5Csqrt%7Bx%2B2%7D%2B2%29%7D%7B+%28%5Csqrt%7Bx%2B2%7D-2%29%2A%28%5Csqrt%7Bx%2B2%7D%2B2%29%7D%3D%5Cfrac%7B+x%2A%28x+-2%29%2A%28%5Csqrt%7Bx%2B2%7D%2B2%29%7D%7B+x%2B2-4%7D%3Dx%2A%28%5Csqrt%7Bx%2B2%7D%2B2%29)
3)
![\frac{x}{ \sqrt{1-x}- \sqrt{1-2x}}](https://tex.z-dn.net/?f=+%5Cfrac%7Bx%7D%7B+%5Csqrt%7B1-x%7D-+%5Csqrt%7B1-2x%7D%7D+)
умножаем числитель и знаменатель на
![\sqrt{1-x}+ \sqrt{1-2x}](https://tex.z-dn.net/?f=%5Csqrt%7B1-x%7D%2B+%5Csqrt%7B1-2x%7D)
![\frac{x}{ \sqrt{1-x}- \sqrt{1-2x}}=\frac{x*(\sqrt{1-x}+ \sqrt{1-2x})}{ (\sqrt{1-x}- \sqrt{1-2x})*(\sqrt{1-x}+ \sqrt{1-2x})}= \\ \\ =\frac{x*(\sqrt{1-x}+ \sqrt{1-2x})}{ (1-x)- (1-2x)}=\frac{x*(\sqrt{1-x}+ \sqrt{1-2x})}{ 1-x-1+2x}=\sqrt{1-x}+ \sqrt{1-2x}](https://tex.z-dn.net/?f=%5Cfrac%7Bx%7D%7B+%5Csqrt%7B1-x%7D-+%5Csqrt%7B1-2x%7D%7D%3D%5Cfrac%7Bx%2A%28%5Csqrt%7B1-x%7D%2B+%5Csqrt%7B1-2x%7D%29%7D%7B+%28%5Csqrt%7B1-x%7D-+%5Csqrt%7B1-2x%7D%29%2A%28%5Csqrt%7B1-x%7D%2B+%5Csqrt%7B1-2x%7D%29%7D%3D+%5C%5C++%5C%5C+%3D%5Cfrac%7Bx%2A%28%5Csqrt%7B1-x%7D%2B+%5Csqrt%7B1-2x%7D%29%7D%7B+%281-x%29-+%281-2x%29%7D%3D%5Cfrac%7Bx%2A%28%5Csqrt%7B1-x%7D%2B+%5Csqrt%7B1-2x%7D%29%7D%7B+1-x-1%2B2x%7D%3D%5Csqrt%7B1-x%7D%2B+%5Csqrt%7B1-2x%7D)