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26 tháng 7 2020

\(\left(x-2\right):2.3=6\)

\(\Leftrightarrow\left(x-2\right):2=2\)

\(\Leftrightarrow\left(x-2\right)=4\)

\(\Leftrightarrow x=4+2=6\)

c) ta có

\(\left[\left(2x+1\right)+1\right]m:2=625\)

\(\Leftrightarrow\left[\left(2x+1\right)+1\right]\left\{\left[\left(2x+1\right)-1\right]:2+1\right\}=1250\)

\(\Leftrightarrow\left(2x+1\right)^2+1-1:2+1=1250\)

\(\Leftrightarrow\left(2x+1\right)^2+1-2+1=1250\)

\(\Leftrightarrow\left(2x+1\right)^2+1-2=1249\)

\(\Leftrightarrow\left(2x+1\right)^2+1=1251\)

\(\Leftrightarrow\left(2x+1\right)^2=1250\)

...

2

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

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

\(\Leftrightarrow\left(x-\frac{1}{2}\right)=\frac{5}{4}:\frac{5}{3}\)

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

\(\Leftrightarrow x-\frac{1}{2}=\frac{3}{4}\)

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

Bài 1:

Ta có: \(4-2\left(x+1\right)=2\)

\(\Leftrightarrow2\left(x+1\right)=2\)

\(\Leftrightarrow x+1=1\)

hay x=0

Bài 2: 

Ta có: \(\left|2x-3\right|-1=2\)

\(\Leftrightarrow\left|2x-3\right|=3\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-3=3\\2x-3=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=6\\2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=0\end{matrix}\right.\)

24 tháng 4 2022

chưa biết

11 tháng 1 2016

a/ 99x+(1+2+...+99)=0

99x+(1+99)x49,5=0

x=5

b/3x-1-2-3+1+2+3+4+...+10=0

3x+4+5+...+10=0

x=-49/3

Bài 2: 

a: =>x=0 hoặc x+3=0

=>x=0 hoặc x=-3

b: =>x-2=0 hoặc 5-x=0

=>x=2 hoặc x=5

c: =>x-1=0

hay x=1

4 tháng 8 2021

3(x+5) -3 = 2(x+1) +7

⇒3x+15-3=2x+2+7

⇒3x+12=2x+9

⇒x=-3

15-(x+2)² = -1

⇒(x+2)2=16

\(\left[{}\begin{matrix}x+2=4\\x+2=-4\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=2\\x=-6\end{matrix}\right.\)

75-(2x+1)³ =11

⇒(2x+1)³=64⇒\(\left[{}\begin{matrix}2x+1=8\\2x+1=-8\end{matrix}\right.\)\(\left[{}\begin{matrix}x=3,5\\x=-4,5\end{matrix}\right.\)

a) ta có: 3(x+5)-3=2(x+1)+7

nên 3x-2x=2+7-15+3

hay x=-3

b) Ta có: \(15-\left(x+2\right)^2=-1\)

nên \(\left(x+2\right)^2=16\)

\(\Leftrightarrow\left[{}\begin{matrix}x+2=4\\x+2=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-6\end{matrix}\right.\)

a) Ta có: \(3\left(x+5\right)-3=2\left(x+1\right)+7\)

\(\Leftrightarrow3x+15-3=2x+2+7\)

\(\Leftrightarrow3x+12=2x+9\)

hay x=-3

b) Ta có: \(15-\left(x+2\right)^2=-1\)

\(\Leftrightarrow\left(x+2\right)^2=16\)

\(\Leftrightarrow\left[{}\begin{matrix}x+2=4\\x+2=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-6\end{matrix}\right.\)

c) Ta có: \(75-\left(2x+1\right)^3=11\)

\(\Leftrightarrow\left(2x+1\right)^3=64\)

\(\Leftrightarrow2x+1=4\)

hay \(x=\dfrac{3}{2}\)

4 tháng 8 2021

a) Ta có: 3(x+5)−3=2(x+1)+7

⇔3x+15−3=2x+2+7

⇔3x+12=2x+9

hay x=-3

b) Ta có: 15−(x+2)2=−1

⇔(x+2)2=16

⇔[x+2=4x+2=−4⇔[x=2x=−6

c) Ta có: 

4 tháng 8 2021

`3(x+5)-3=2(x+1)+7`

`3x+15-3=2x+2+7`

`x=-3`

.

`15-(x+2)^2=-1`

`(x+2)^2=16`

`(x+2)^2=4^2=(-4)^2`

`[(x+2=4),(x+2=-4):}`

`[(x=2),(x=-6):}`

.

`75-(2x+1)^3=11`

`(2x+1)^3=64`

`(2x+1)^2=4^3`

`2x+1=4`

`x=3/2`

4 tháng 8 2021

3(x+5)-3=2(x+1)+7

3x+15-3=2x+2+7

x=-3

.

15-(x+2)2=-1

(x+2)2=16

(x+2)2=42=(-4)2

[x+2=4x+2=-4