Đề bài là tìm số hữu tỉ x nha

\(\frac{3x-1}{8}+\frac{3x+18}{11}=\frac{3x}{7}+\frac{3x+20}{13}\)

\(\Rightarrow\frac{1001\left(3x-1\right)}{8008}+\frac{728\left(3x+18\right)}{8008}=\frac{1144.3x}{8008}+\frac{616\left(3x+20\right)}{8008}\)

\(\Rightarrow3003x-1001+2184x+13104x=3432x+1848x+12320\)\

\(\Rightarrow\)\(19111x=13321\Rightarrow x=\frac{13321}{19111}\)

c) 3,6-|x-0,4|=0

     |x-0,4|=3,6-0

     |x-0,4|=3,6

* x-0,4 =3,6                              * x-0,4=-3,6

       x=3,6+0,4                                x= -3,6+0,4

       x=4                                         x=-3,2

         vậy x=4 hoặc x=-3,2

a) 2/3 : x + 5/7 = 3/10

=> 2/3 : x = 3/10 - 5/7 

=> 2/3 : x = -29/70

=> x = 2/3 : -29/70 

=> x = -140/87

b) 3/4 . x - 1/2 = 3/7

3/4 . x = 3/7 + 1/2

3/4 . x = 13/14

x = 13/14 : 3/4 

x = 26/21

c) 3,6 - | x - 0,4 | = 0 

Có 2 TH : 

-) x = 0,4 

-) x - 0 ,4 = -3,6

=> x = -3,2

Chúc bn học tốt 😊😊

Đặt \(\frac{a}{b}=\frac{c}{d}=k\Rightarrow a=bk;c=dk\)

\(\text{Khi đó }\frac{5a+7b}{11a-13b}=\frac{5bk+7b}{11bk-13b}=\frac{b\left(5k+7\right)}{b\left(11k-13\right)}=\frac{5k+7}{11k-13}\left(1\right);\)

\(\frac{5c+7d}{11c-13d}=\frac{5dk+7d}{11dk-13d}=\frac{d\left(5k+7\right)}{d\left(11k-13\right)}=\frac{5k+7}{11k-13}\left(2\right)\)

\(\text{Từ }\left(1\right)\text{và }\left(2\right)\Rightarrow\frac{5a+7b}{11a-13b}=\frac{5c+7d}{11c-13d}\left(\text{ĐPCM}\right)\)

a.Để x<0 thì a-5<0 suy ra: a<5

b.Để x>0 thì a-5>0 suy ra: a>5

\(\left(-\frac{2}{3}+\frac{3}{7}\right):\frac{4}{5}+\left(-\frac{1}{3}+\frac{4}{7}\right):\frac{4}{5}\)

= \(\left(-\frac{14}{21}+\frac{9}{21}\right).\frac{5}{4}+\left(-\frac{7}{21}+\frac{12}{21}\right).\frac{5}{4}\)

= \(-\frac{5}{21}.\frac{5}{4}+\frac{5}{21}.\frac{5}{4}\)

= \(\frac{5}{4}.\left(-\frac{5}{21}+\frac{5}{21}\right)\)

= \(\frac{5}{4}.0\)

= \(0\)

Chúc bạn học tốt !!!

\(\left(\frac{-2}{3}+\frac{3}{7}\right):\frac{4}{5}+\left(-\frac{1}{3}+\frac{4}{7}\right):\frac{4}{5}\)

\(=\left(\frac{3}{7}-\frac{2}{3}\right).\frac{4}{5}+\left(\frac{4}{7}-\frac{1}{3}\right).\frac{4}{5}\)

\(=\left(\frac{3}{7}-\frac{2}{3}+\frac{4}{7}-\frac{1}{3}\right).\frac{4}{5}\)

\(=\left[\left(\frac{3}{7}+\frac{4}{7}\right)-\left(\frac{2}{3}+\frac{1}{3}\right)\right].\frac{4}{5}\)

\(=\left(1-1\right).\frac{4}{5}\)

\(=0.\frac{4}{5}\)

\(=0\)

\(A=\left(\frac{1}{10}-1\right).\left(\frac{1}{11}-1\right).\left(\frac{1}{12}-1\right)...\left(\frac{1}{99}-1\right).\left(\frac{1}{100}-1\right)\)(91 cặp số)

\(=\frac{-9}{10}.\frac{-10}{11}.\frac{-11}{12}....\frac{-98}{99}.\frac{-99}{100}\)(91 thừa số)

\(=-\left(\frac{9}{10}.\frac{10}{11}.\frac{11}{12}....\frac{98}{99}.\frac{99}{100}\right)\)

\(=-\frac{9}{100}\)

\(=-0,09\)

Vậy A = - 0,09

Gọi pt đề bài là (*)

Ta có (*) <=> x - 1 = 3²

<=> x = 10

\(\sqrt{x-1}=3.\left(2018+2019+2020\right)^0\)

\(\sqrt{x-1}=3\)

\(\sqrt{x-1}^2=3^2\)

\(x-1=9\)

\(x=9+1\)

\(\Rightarrow x=10\)

=>3x+2⁴=7 . 5²

=>3x=175:2⁴

=>x=10,9375:3

=>x=3,6458

ko chắc 

tham kảo rồi k đúng cho mk nha

( 3x  + 2⁴ ) . 5⁴ = 7 . 5⁶ 

3x + 2⁴ = 7 . 5⁶ : 5⁴

3x + 16 = 7 . 5² 

3x + 16 = 175

3x = 159

x = 53 

Xtudy well 

\(a,\frac{8}{x}=\frac{x}{4}\)

\(=>x\cdot x=8\cdot4\)

\(=>x^2=32\)

\(=>x=\sqrt{32}\)

\(c,\frac{2x+3}{6}=\frac{x+1}{-8}\)

\(=>-8\cdot\left(2x+3\right)=6\cdot\left(x+1\right)\)

\(=>-16x-24=6x+6\)

\(=>-16x-6x=6+24\)

\(=>-22x=30\)

\(=>x=\frac{30}{-22}=-\frac{15}{11}\)

hai góc kề bù có tổng bằng 150^o??

sai đề rồi hai góc kề bù tạo bởi hai tia đối nhau có tổng số đo bằng 180^o