Решение во вложении-----------
- на +=-
+ на +=+
какой именно пример?
3*(x^2+8*x+16)-10*x-32=0
3*x^2+24*x+48-10*x-32=0
3*x^2+14*x+16=0
D=14^2 - 4 * 3 * 16 = 4
x1 = (-14-2) / 3*2 = -2 2/3
<span>x2 = (-14+2) / 3*2 = -2</span>
Выразим с первого уравнения системы х и после подставим во второе уравнение:
![\left \{ {{x-7y=0 \ =>x=7y} \atop {12x+y=17}} \right. \\ 12x+y=17 \\ 12*(7y)+y=17 \\ 85y=17 \\ y= \frac{17}{85}= \frac{1}{5}=0,2 \\ x=7y=7*0,2=1,4 \\ \left \{ {{x=1,4} \atop {y=0.2}} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Bx-7y%3D0+%5C+%3D%3Ex%3D7y%7D+%5Catop+%7B12x%2By%3D17%7D%7D+%5Cright.++%5C%5C+12x%2By%3D17+%5C%5C+12%2A%287y%29%2By%3D17+%5C%5C+85y%3D17+%5C%5C+y%3D+%5Cfrac%7B17%7D%7B85%7D%3D+%5Cfrac%7B1%7D%7B5%7D%3D0%2C2+%5C%5C+x%3D7y%3D7%2A0%2C2%3D1%2C4+%5C%5C++%5Cleft+%5C%7B+%7B%7Bx%3D1%2C4%7D+%5Catop+%7By%3D0.2%7D%7D+%5Cright.++)
<span>8x-6x = 7,5+1,5
2х= 9
х=9:2
х=4.5
4х-9х+6=46
-5х+6=46
-5х=46-6
-5х=40
х=-8
8х-6+х=9х-6
8х+х=9х
9х=9х
</span>