bài 22: tìm x,biết
a, (x+4)2-(x+1) (x-1) =16
Mọi người giải thích hộ e với!
Bài 22: Tìm x, biết.
a, 25x2-9=0
b, (x+4)2-(x+1) (x-1)
c, (2x-1)2+(x+3)2-5(x+7) (x-7)=0
Mọi người trình bày đầy đủ hộ e với!
Tìm x e Z biết
a, | -5 | + | x - 1 | = | 7 |
b, 2 . | 2x - 4 | - | - 4 | = | - 50 |
giúp mình với nha mọi người !
Thanks !
a) Ta có: \(\left|-5\right|+\left|x-1\right|=\left|7\right|\)
\(\Leftrightarrow\left|x-1\right|+5=7\)
\(\Leftrightarrow\left|x-1\right|=2\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=2\\x-1=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-1\end{matrix}\right.\)
Vậy: \(x\in\left\{3;-1\right\}\)
b) Ta có: \(2\cdot\left|2x-4\right|-\left|-4\right|=\left|-50\right|\)
\(\Leftrightarrow4\cdot\left|x-2\right|-4=50\)
\(\Leftrightarrow4\cdot\left|x-2\right|=54\)
\(\Leftrightarrow\left|x-2\right|=\dfrac{27}{2}\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=\dfrac{27}{2}\\x-2=-\dfrac{27}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{31}{2}\left(loại\right)\\x=-\dfrac{23}{2}\left(loại\right)\end{matrix}\right.\)
Vậy: \(x\in\varnothing\)
a, | -5 | + | x-1 | = | 7 |
5 + | x - 1 | = 7
| x - 1 | = 2
TH1 x -1 = 2
x = 3
TH2 x -1 = -2
x= -1
Tìm X biết
a)22.x-5=32
b)42x-1=64
c)(2.X+2)2=121
d)2x3-1=255
mn ơi giúp mik với mik cần gấp
\(a,\Rightarrow2^{2x-5}=2^5\Rightarrow2x-5=5\Rightarrow x=5\\ b,\Rightarrow4^{2x-1}=4^3\Rightarrow2x-1=3\Rightarrow x=2\\ c,\Rightarrow\left[{}\begin{matrix}2x+2=11\\2x+2=-11\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\x=-\dfrac{13}{2}\end{matrix}\right.\\ d,\Rightarrow2^{x^3}=256=2^8\Rightarrow x^3=8\Rightarrow x=2\)
a)
\(2^{2x-5}=2^5\)
2x-5=5
2x=10
x=5
b)
\(4^{2x-1}=4^3\)
2x-1=3
2x=4
x=2
c)
\(\left(2x+2\right)^2=11^2\)
2x+2=11
2x=9
x=9/2
a) \(2^{2x-5}=32\)
⇒\(2^{2x-5}=2^5\)
⇒\(2x-5=5\)
⇒\(2x=10\)
⇒\(x=5\)
Bài 1: Tính
a) ( - 153 ) + ( - 45 )
b) 65 - ( - 274 )
c) 327 + ( - 47 )
d) 23 - 115
Bài 2: Tìm , biết
a) x + 75 = 21
b) ( - 30 ) - x = - 45
Các bạn giúp hộ với mình cần gấp.
Bài 1:
a: =-153-45=-198
b: =65+274=339
Bài 1: Tìm x biết
a) (2x + 1)2 - 4(x + 2)2 = 9;
b) (x + 3)2 - (x - 4)( x + 8) = 1;
a: Ta có: \(\left(2x+1\right)^2-4\left(x+2\right)^2=9\)
\(\Leftrightarrow4x^2+4x+1-4x^2-16x-16=9\)
\(\Leftrightarrow-12x=24\)
hay x=-2
b: Ta có: \(\left(x+3\right)^2-\left(x-4\right)\left(x+8\right)=1\)
\(\Leftrightarrow x^2+6x+9-x^2-4x+32=1\)
\(\Leftrightarrow2x=-40\)
hay x=-20
Bài 1: Tìm x biết
a) 4\(\sqrt{2x-1}\) > 8
b)\(2\sqrt{x}-1>3\)
a) `4\sqrt(2x-1)>8`
`<=>\sqrt(2x-1)>2`
`<=>2x-1>4`
`<=>x>5/2`
b) `2\sqrtx-1>3`
`<=>2\sqrtx>4`
`<=>\sqrtx>2`
`<=>x>4`
a) Ta có: \(4\sqrt{2x-1}>8\)
\(\Leftrightarrow2x-1>4\)
\(\Leftrightarrow2x>5\)
hay \(x>\dfrac{5}{2}\)
b) Ta có: \(2\sqrt{x}-1>3\)
\(\Leftrightarrow\sqrt{x}>2\)
hay x>4
bài 1: Tìm x biết
a) 2.x+(-5)=-18
b) 3.3=81
c) 64-4.(5-x)=40
a: =>2x=-18+5=-13
=>x=-13/2
b: =>3^x-1=81
=>x-1=4
=>x=5
c: =>4(5-x)=24
=>5-x=6
=>x=-1
Bài 1: Tìm số nguyên x biết
a) x/4= 1/x
b) 1/5= x:4-1/10
a) \(\dfrac{x}{4}\)=\(\dfrac{1}{x}\)→x2=4→x=2 hoặc x=-2
b) \(\dfrac{1}{5}\) = x:4-\(\dfrac{1}{10}\)→x:4=\(\dfrac{1}{5}\)+\(\dfrac{1}{10}\)→x:4=\(\dfrac{2+1}{10}\)→x:4=\(\dfrac{3}{10}\)→x=\(\dfrac{3}{10}\)x4→x=\(\dfrac{12}{10}\)→x=\(\dfrac{6}{5}\)
Bài 2:Tìm x biết
A, -\(\dfrac{13}{20}\)+x=-\(\dfrac{11}{15}\) B,( x-3,5):3\(\dfrac{1}{2}\)-2,5=-1\(\dfrac{3}{4}\)
\(a,-\dfrac{13}{20}+x=\dfrac{-11}{15}\\ \Rightarrow x=\dfrac{-11}{15}+\dfrac{13}{20}\\ \Rightarrow x=-\dfrac{1}{12}\\ b,\left(x-3,5\right):3\dfrac{1}{2}-2,5=-1\dfrac{3}{4}\\ \Rightarrow\left(x-\dfrac{7}{2}\right):\dfrac{7}{2}-\dfrac{5}{2}=\dfrac{-7}{4}\\ \Rightarrow\left(x-\dfrac{7}{2}\right):\dfrac{7}{2}=\dfrac{3}{4}\\ \Rightarrow x-\dfrac{7}{2}=\dfrac{21}{8}\\ \Rightarrow x=\dfrac{49}{8}\)