A1=4 d=3
a13=?
a13=a1+12d
a13=4+36=40
Х+4 х+3 х-2
------- -х +5= -------- - ---------
5 3 2
х+4-5х+25 2х+6 -3х+6
------------------ = ---------------------
5 6
29 -4х 12-х
----------- = --------------- домножим обе части на 30
5 6
6*(29 -4х)=5*(12-х)
174 -24х=60-5х
19х=114
х=6
1) ![5,04:(104,2-x)=1,2](https://tex.z-dn.net/?f=5%2C04%3A%28104%2C2-x%29%3D1%2C2)
![104,2-x=5,04:1,2](https://tex.z-dn.net/?f=104%2C2-x%3D5%2C04%3A1%2C2)
![104,2-x=4,2](https://tex.z-dn.net/?f=104%2C2-x%3D4%2C2)
![x=100](https://tex.z-dn.net/?f=x%3D100)
_______________________________________________________
(это проверка)
![5,04:4,2=1,2](https://tex.z-dn.net/?f=5%2C04%3A4%2C2%3D1%2C2)
![1,2=1,2](https://tex.z-dn.net/?f=1%2C2%3D1%2C2)
=======================================================
2) ![1,2x+4,5x-0,7=1,01](https://tex.z-dn.net/?f=1%2C2x%2B4%2C5x-0%2C7%3D1%2C01)
![5,7x-0,7=1,01](https://tex.z-dn.net/?f=5%2C7x-0%2C7%3D1%2C01)
![5,7x=1,01+0,7](https://tex.z-dn.net/?f=5%2C7x%3D1%2C01%2B0%2C7)
![5,7x=1,71](https://tex.z-dn.net/?f=5%2C7x%3D1%2C71)
![x=1,71:5,7](https://tex.z-dn.net/?f=x%3D1%2C71%3A5%2C7)
![x=0,3](https://tex.z-dn.net/?f=x%3D0%2C3)
_______________________________________________________
![1,2\cdot0,3+4,5\cdot0,3-0,7=1,01](https://tex.z-dn.net/?f=1%2C2%5Ccdot0%2C3%2B4%2C5%5Ccdot0%2C3-0%2C7%3D1%2C01)
![0,36+1,35-0,7=1,01](https://tex.z-dn.net/?f=0%2C36%2B1%2C35-0%2C7%3D1%2C01)
![1,01=1,01](https://tex.z-dn.net/?f=1%2C01%3D1%2C01)
Ответ:
4
Объяснение:
(x - 3)(x - 4) = 0 x - 3 ≠ 0 ⇒ x ≠ 3
x - 4 = 0
x = 4