Question

Решите пожалуйста уравнения:
1 1/3х+8=1/3х-7

1 1/5х-9=-4/5х+4

-2 2/7х+9=-2/7х-5

2 1/3х+2=4-2 2/3х
Дам 100 балов

Answer 1

Ответ:

Пошаговое объяснение:

$1\dfrac{1}{3}x+8=\dfrac{1}{3}x-7\\\\\star\;\;1\dfrac{1}{3}=\dfrac{1\cdot3+1}{3}=\dfrac{4}{3}\;\;\star\\\\\dfrac{4}{3}x+8=\dfrac{1}{3}x-7\;\;|\cdot3\\\\4x+24=x-21\\\\4x-x=-21-24\\\\3x=-45\\\\x=\dfrac{-45}{3}\\\\x=-15$

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$1\dfrac{1}{5}x-9=-\dfrac{4}{5}x+4\\\\\star\;\;1\dfrac{1}{5}=\dfrac{1\cdot5+1}{5}=\dfrac{6}{5}\;\;\star\\\\\dfrac{6}{5}x-9=-\dfrac{4}{5}x+4\;\;|\cdot5\\\\6x-45=-4x+20\\\\6x+4x=20+45\\\\10x=65\\\\x=\dfrac{65}{10}\\\\x=6,5$

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$-2\dfrac{2}{7}x+9=-\dfrac{2}{7}x-5\\\\\star\;\;-2\dfrac{2}{7}=-\dfrac{2\cdot7+2}{7}=-\dfrac{16}{7}\;\;\star\\\\-\dfrac{16}{7}x+9=-\dfrac{2}{7}x-5\;\;|\cdot7\\\\-16x+63=-2x-35\\\\-16x+2x=-35-63\\\\-14x=-98\\\\x=\dfrac{-98}{-14}\\\\x=7$

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2 1/3x+2=4-2 2/3x

*** 2 1/3 = (2*3+1)/3=7/3 ***

7/3x+2=4-8/3x

7x+6=12-8x

7x+8x=12-6

15x=6

x=6/15

x=0,4

Answer 2

Ответ:

1. х = -15     2. х = 6 1/2   3. х = 7    4. х = 2/5  

Пошаговое объяснение:

1. 1 1/3х+8=1/3х-7

4/3х - 1/3х = -7 - 8

3/3х = -15   х = -15

2. 1 1/5х-9 = -4/5х+4

6/5х + 4/5х = 4 + 9

10/5х = 13    2х = 13   х = 13/2    х = 6 1/2

3. -2 2/7х+9 = -2/7х-5

-16/7х + 2/7х = -5 - 9

-14/7х = -14    -2х = -14   х = -14/(-2)    х = 7

4. 2 1/3х+2 = 4-2 2/3х

7/3х + 8/3х = 4 - 2

15/3х = 2    5х = 2    х = 2/5