Здесь нельзя же такие задачи вставлять, экзаменационные
1)
![2x+3y=5\\ x-y=2\\ x+4y=a\\ \\ x=\frac{5-3y}{2}\\ \frac{5-3y}{2}-y=2\\ 5-5y=4\\ y=\frac{1}{5}\\ 2(a-\frac{4}{5})+\frac{3}{5}=5\\ a=3\\ Otvet \ a=3 ](https://tex.z-dn.net/?f=2x%2B3y%3D5%5C%5C%0Ax-y%3D2%5C%5C%0Ax%2B4y%3Da%5C%5C%0A%5C%5C%0Ax%3D%5Cfrac%7B5-3y%7D%7B2%7D%5C%5C%0A%5Cfrac%7B5-3y%7D%7B2%7D-y%3D2%5C%5C%0A5-5y%3D4%5C%5C%0Ay%3D%5Cfrac%7B1%7D%7B5%7D%5C%5C%0A2%28a-%5Cfrac%7B4%7D%7B5%7D%29%2B%5Cfrac%7B3%7D%7B5%7D%3D5%5C%5C%0Aa%3D3%5C%5C%0AOtvet+%5C+a%3D3%0A)
2)
![\frac{3}{k+1}=(k-1)=\frac{k+1}{3}\\ k=2](https://tex.z-dn.net/?f=%5Cfrac%7B3%7D%7Bk%2B1%7D%3D%28k-1%29%3D%5Cfrac%7Bk%2B1%7D%7B3%7D%5C%5C%0Ak%3D2)
3)
![4x-1 = (k+3)x-k-3 kx+3x-k-3-4x+1 = 0 (k-1)x-k-2 = 0 \\ x=\frac{k+2}{k-1}\\ ](https://tex.z-dn.net/?f=4x-1+%3D+%28k%2B3%29x-k-3+%0A%0Akx%2B3x-k-3-4x%2B1+%3D+0+%0A%0A%28k-1%29x-k-2+%3D+0+%5C%5C%0Ax%3D%5Cfrac%7Bk%2B2%7D%7Bk-1%7D%5C%5C%0A)
отудого k (-2;1)
4)
![(a^2-4)x+5 = 0\\ x=\frac{5}{a^2-4}\\ a^2-4=0\\ a=+-2\\ 2*-2=-4](https://tex.z-dn.net/?f=%28a%5E2-4%29x%2B5+%3D+0%5C%5C%0Ax%3D%5Cfrac%7B5%7D%7Ba%5E2-4%7D%5C%5C%0Aa%5E2-4%3D0%5C%5C%0Aa%3D%2B-2%5C%5C+2%2A-2%3D-4)
Решение:
25х3-10х2+х=0
x(25x²-10x+1)=0
x1=0
25x²-10x+1=0
(5x-1)²=0
x2=x3=0.2
<span>Уравнение имеет 3 корня, два из них равны между собой.</span>
0x4645655654&:!$(;"($84-(_8'!_
9 * 10 в степени - 2 * 9 * 10 в степени -4 * 9 * 10 в степени - 5 =
9 * 9 * 9 * 10 в степени (-2-4-5) = 729 * 10 в степени -11