Тут явная пропорция
1)
![\frac{x+5}{x-5}= \frac{x-5}{x+5}](https://tex.z-dn.net/?f=+%5Cfrac%7Bx%2B5%7D%7Bx-5%7D%3D+%5Cfrac%7Bx-5%7D%7Bx%2B5%7D)
(x+5)²=(x-5)²
либо х+5=х-5, чего не может быть
либо x+5=-(x-5)
x+5=5-x
2x=0
x=0
3)
![\frac{x-4}{2}=\frac{10+2x}{x}](https://tex.z-dn.net/?f=%5Cfrac%7Bx-4%7D%7B2%7D%3D%5Cfrac%7B10%2B2x%7D%7Bx%7D)
x(x-4)=2(10+2x)
x²-4x=20+4x
x²-8x-20=0
D=8²+4*20=64+80=144
√D=12
x₁=(8-12)/2=-2
x₂=(8+12)/2=10
A-b²
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мог бы побольше очков дать
Ответ:
(1;-3), (2;4), (1;2), (-1;4), (3;1)
Объяснение:
413.
{2х-3у=11
{5х+у=2 |×3
{2х-3у=11
{15х+3у=6
*+*
{17х=17
{у=2-5х
{х=1
{у=2-5×1=-3
(1;-3)
416.
{5х+у=14 |×2
{3х-2у=-2
{10х+2у=28
{3х-2у=-2
*+*
{13х=26
{у=14-5х
{х=2
{у=14-5×2=4
(2;4)
419.
{х+3у=7
{х+2у=5 |×(-1)
{х+3у=7
{-х-2у=-5
*+*
{у=2
{х=5-2у=5-2×2=1
(1;2)
422.
{2х+3у=10
{х-2у=-9 |×(-2)
{2х+3у=10
{-2х+4у=18
*+*
{7у=28
{х=-9+2у
{у=4
{х=-9+2×4=-1
(-1;4)
425.
{х-у=3 |×(-3)
{3х+4у=2
{-3х+3у=-9
{3х+4у=2
*+*
{7у=-7
{х=3+у
{у=-1
{х=3-1=2
(2;-1)
428.
{х-4у=-1 |×(-3)
{3х-у=8
{-3ч+12у=3
{3х-у=8
*+*
{11у=11
{х=4у-1
{у=1
{х=4×1-1=3
(3;1)
{x-6y=17 {6x=30 {х=5 {х=5 {х=5
{5x+6y=13, {х-6у=17, {5-6у=17, {-6y=12, {у=-2