1) 4281+328+219 = (4281 + 219) + 328 = 4500 + 328 = 4828
-15,76+34,22-24,72+4,43-81,16=-82,99
4x+5/13=8/9
4x=8/9 - 5/13
4x= (8*13-5*9)/(9*13)
4x=54/117
x=3/26
![\displaystyle \frac{3}{x-3}+\frac{6}{x-2}=6~~~|\bigg|\cdot(x-3)(x-2)\\ \\ 3(x-2)+6(x-3)=6(x-3)(x-2)~~|:3\\ x-2+2x-6=2(x^2 -5x+6)\\ 3x-8=2x^2-10x+12\\ 2x^2-13x+20=0\\ D=(-13)^2-4\cdot2\cdot20=9](https://tex.z-dn.net/?f=+%5Cdisplaystyle+%5Cfrac%7B3%7D%7Bx-3%7D%2B%5Cfrac%7B6%7D%7Bx-2%7D%3D6~~~%7C%5Cbigg%7C%5Ccdot%28x-3%29%28x-2%29%5C%5C+%5C%5C+3%28x-2%29%2B6%28x-3%29%3D6%28x-3%29%28x-2%29~~%7C%3A3%5C%5C+x-2%2B2x-6%3D2%28x%5E2++-5x%2B6%29%5C%5C+3x-8%3D2x%5E2-10x%2B12%5C%5C+2x%5E2-13x%2B20%3D0%5C%5C+D%3D%28-13%29%5E2-4%5Ccdot2%5Ccdot20%3D9+)
![x_1=2.5](https://tex.z-dn.net/?f=+x_1%3D2.5+)
![x_2=4](https://tex.z-dn.net/?f=+x_2%3D4+)
Задание 7.
![4xy+2(x-y)^2=4xy+2(x^2-2xy+y^2)=4xy+2x^2-4xy+2y^2=2(x^2+y^2)](https://tex.z-dn.net/?f=+4xy%2B2%28x-y%29%5E2%3D4xy%2B2%28x%5E2-2xy%2By%5E2%29%3D4xy%2B2x%5E2-4xy%2B2y%5E2%3D2%28x%5E2%2By%5E2%29+)
Подставим значения, получим ![2\cdot((\sqrt{7} )^2+(\sqrt{5} )^2)=2\cdot(7+5)=2\cdot12=24](https://tex.z-dn.net/?f=+2%5Ccdot%28%28%5Csqrt%7B7%7D+%29%5E2%2B%28%5Csqrt%7B5%7D+%29%5E2%29%3D2%5Ccdot%287%2B5%29%3D2%5Ccdot12%3D24+)
задание 8. ![x^2>16](https://tex.z-dn.net/?f=+x%5E2%3E16+)
![|x|>4~~~\Rightarrow~~~\left[\begin{array}{ccc}x<-4\\ x>4\end{array}\right](https://tex.z-dn.net/?f=+%7Cx%7C%3E4~~~%5CRightarrow~~~%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx%3C-4%5C%5C+x%3E4%5Cend%7Barray%7D%5Cright+)
Ответ: 1)
Решение:
4х +3(х-2)=8
4х +3х -6=8
7х=8+6
7х=14
х=14 :7
х=14/7=2
Ответ: х=2