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1 tháng 1

\(2x+\frac12=\frac79\)

\(2x=\frac79-\frac12\)

\(2x=\frac{14}{18}-\frac{9}{18}\)

\(2x=\frac{5}{18}\)

\(x=\frac{5}{18}:2\)

\(x=\frac{5}{18}\times\frac12=\frac{5}{36}\)

a: \(\Leftrightarrow\left(2x-2\right)\cdot\dfrac{3}{4}=-6-\dfrac{1}{3}=-\dfrac{19}{3}\)

\(\Leftrightarrow2x-2=-\dfrac{19}{3}:\dfrac{3}{4}=-\dfrac{76}{9}\)

=>2x=-58/9

hay x=-29/9

b: \(\Leftrightarrow\left(\dfrac{44}{7}x+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)

\(\Leftrightarrow x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{5}{7}\)

\(\Leftrightarrow x\cdot\dfrac{44}{7}=-\dfrac{8}{7}\)

hay x=-2/11

e: \(\left(2x+\dfrac{3}{5}\right)^2=\dfrac{9}{25}\)

\(\Leftrightarrow\left[{}\begin{matrix}2x+\dfrac{3}{5}=\dfrac{3}{5}\\2x+\dfrac{3}{5}=-\dfrac{3}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-\dfrac{3}{5}\end{matrix}\right.\)

25 tháng 6 2019

\(A=\frac{4^5.9^4-2.6^9}{2^{10}.3^8-6^8.20}\)

\(A=\frac{\left(2^2\right)^5.\left(3^2\right)^4-2.\left(2.3\right)^9}{2^{10}.3^8-\left(2.3\right)^8.2^2.5}\)

\(A=\frac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8-2^{10}.3^8.5}\)

\(A=\frac{2^{10}.\left(3^8-3^9\right)}{2^{10}.3^8.\left(1-5\right)}=\frac{3^8-3^9}{3^8.\left(-4\right)}=\frac{3^8.\left(1-3\right)}{3^8.\left(-4\right)}=\frac{-2}{-4}=\frac{1}{2}\)

Vậy A = \(\frac{1}{2}\)

\(B=\frac{2^{19}.27^3+15.4^9.9^4}{6^9.2^{10}+12^{10}}\)

\(B=\frac{2^{19}.\left(3^3\right)^3+3.5.\left(2^2\right)^9.\left(3^2\right)^4}{\left(2.3\right)^9.2^{10}+\left(2^2.3\right)^{10}}\)

\(B=\frac{2^{19}.3^9+3.5.2^{18}.3^8}{2^9.3^9.2^{10}+2^{20}.3^{10}}\)

\(B=\frac{2^{19}.3^9+3^9.2^{18}.5}{2^{19}.3^9+2^{20}.3^{10}}\)

\(B=\frac{2^{18}.3^9.\left(2+5\right)}{2^{19}.3^9\left(1+2.3\right)}=\frac{7}{2.7}=\frac{1}{2}\)

Vậy B = \(\frac{1}{2}\)

10 tháng 9 2020

a) \(\frac{1}{2}x+\frac{2}{5}=\frac{7}{5}\Leftrightarrow\frac{x}{2}=\frac{7}{5}-\frac{2}{5}=\frac{5}{5}=1\Leftrightarrow x=2\)

b) \(\frac{25}{9}-\frac{3}{4}\left(x+1\right)=\frac{7}{9}\Leftrightarrow\frac{3}{4}\left(x+1\right)=\frac{25}{9}-\frac{7}{9}=\frac{18}{9}=2\)

\(\Leftrightarrow x+1=2.\frac{4}{3}\Leftrightarrow x=\frac{5}{3}\)

Bài làm :

\(a,\frac{1}{2}x+\frac{2}{5}=\frac{7}{5}\)

\(\Rightarrow\frac{1}{2}x=\frac{7}{5}-\frac{2}{5}\)

\(\Rightarrow\frac{1}{2}x=1\)

\(\Rightarrow x=2\)

Vậy x = 2 .

\(b,\frac{25}{9}-\frac{3}{4}\left(x+1\right)=\frac{7}{9}\)

\(\Rightarrow\frac{3}{4}\left(x+1\right)=\frac{25}{9}-\frac{7}{9}\)

\(\Rightarrow\frac{3}{4}\left(x+1\right)=2\)

\(\Rightarrow x+1=\frac{8}{3}\)

\(\Rightarrow x=\frac{5}{3}\)

Vậy \(x=\frac{5}{3}\) .

Học tốt nhé

2 tháng 10 2017

câu E

\(\left\{{}\begin{matrix}x\ne\dfrac{5}{2}\\\left(2x-5\right)\left(5-2x\right)=-\left(\dfrac{3}{2}\right)^4\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x\ne\dfrac{5}{2}\\\left|2x-5\right|=\left(\dfrac{3}{2}\right)^2\end{matrix}\right.\)

\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x< \dfrac{5}{2}\\2x-5=-\left(\dfrac{3}{2}\right)^2\Rightarrow x=\dfrac{11}{8}< \dfrac{5}{2}\left(n\right)\end{matrix}\right.\\\left\{{}\begin{matrix}x>\dfrac{5}{2}\\2x-5=\left(\dfrac{3}{2}\right)^2\Rightarrow x=\dfrac{29}{8}>\dfrac{5}{2}\left(n\right)\end{matrix}\right.\end{matrix}\right.\)

câu F (bạn cho vào lớp 7.2=lớp 14 nhé. )

13 tháng 11 2016

a) 2|2/3 - x| = 1/2

|2/3 - x| = 1/4

|2/3 - x| = 1/4 hoặc |2/3 - x| = -1/4

Xét 2 TH...

a: 4x+9=0

=>4x=-9

=>x=-9/4

b: -5x+6=0

=>-5x=-6

=>x=6/5

c: 7-2x=0

=>2x=7

=>x=7/2

d: 2x+5=0

=>2x=-5

=>x=-5/2

e: 2x+6=0

=>2x=-6

=>x=-3

g: 3x-1/4=0

=>3x=1/4

hay x=1/12