Tìm x:
a) √x = 3
b) √x = 6
c) √x = 8
d) √x = 12
e) 2√x = 10
f) 3√x = 21
g) √x = 8
h) 2 + √x = 11
Tìm số tự nhiên x ( đưa vê cùng 1 cơ số )
a , 2 mũ x = 2 mũ 3
b , 4 mũ x = 6
c , 11x = 1331
d , 2 mũ x + 4 = 12
e , 3 mũ x - 4 = 23
a: \(2^x=2^3\)
nên x=3
c: \(11^x=1331\)
nên x=3
d: \(2^x+4=12\)
nên \(2^x=8\)
hay x=3
tìm x:
a)3(2x-3)+2(2-x)=-3
b)2x(x2-2)+x2(1-2x)-x2=-12
c)3x(2x+3)-(2x+5)(3x-2)=8
d)4x(x - 1) - 3(x2-5)-x2=(x-3)-(x+4)
e)2(3x-1)(2x+5)-6(2x-1)(x+2)=-6
a: Ta có: \(3\left(2x-3\right)+2\left(2-x\right)=-3\)
\(\Leftrightarrow6x-9+4-2x=-3\)
\(\Leftrightarrow4x=2\)
hay \(x=\dfrac{1}{2}\)
Tìm x:
a)x(x+4)+(5+x)(5-x)=3
b)(2x-3)^2=(4x+3)^2
mình cảm ơn
\(a,\Rightarrow x^2+4x+25-x^2=3\\ \Rightarrow4x=-22\Rightarrow x=-\dfrac{11}{2}\\ b,\Rightarrow\left(2x-3-4x-3\right)\left(2x-3+4x+3\right)=0\\ \Rightarrow6x\left(-2x-6\right)=0\Rightarrow\left[{}\begin{matrix}x=-3\\x=0\end{matrix}\right.\)
Tìm x:
a)x+3/4=5/3
b)x-2/3=7/2
a) x + \(\dfrac{3}{4}\) = \(\dfrac{5}{3}\)
x = \(\dfrac{5}{3}\) - \(\dfrac{3}{4}\)
x = \(\dfrac{20}{12}\) - \(\dfrac{9}{12}\)
x = \(\dfrac{11}{12}\)
b) x - \(\dfrac{2}{3}\) = \(\dfrac{7}{2}\)
x = \(\dfrac{7}{2}\) + \(\dfrac{2}{3}\)
x = \(\dfrac{21}{6}\) + \(\dfrac{4}{6}\)
x = \(\dfrac{25}{6}\)
Bài4:Tìm x:
a. 124 + (118 – x) = 217 b. 7x – 8 = 713 c. x- 36:18 = 12 d. (x- 36):18 = 12 e. (x-47) -115 = 0 f. 315 + (146 – x) = 401 | g. (6x – 39 ) : 3 = 201 h. 23 + 3x = 56 : 53 i. 5x + x = 39 – 311:39 j. 7x – x = 521 : 519 + 3.22 - 70 k. 7x – 2x = 617: 615 + 44 : 11 l. 0 : x = 0 | m. 3x = 9 n. 4x = 64 o. 2x = 16 p. 9x- 1 = 9 q. x4 = 16 r. 2x : 25 = 1 |
Bài4:Tínhnhanh
1. 58.75 + 58.50 – 58.25 2. 27.39 + 27.63 – 2.27 3. 128.46 + 128.32 + 128.22 4. 87.23 + 13.93 + 70.87
| 5. 12.35 + 35.182 – 35.94 6. 48.19 + 48.115 + 134.52 7. 27.121 – 87.27 + 73.34 8. 136.23 + 136.17 – 40.36 9. 125.98 – 125.46 – 52.25 | 10. 17.93 + 116.83 + 17.233 11. 5.23 + 35.41 + 64.65 12. 29.87 – 29.23 + 64.71 13. 19.27 + 47.81 + 19.20
|
b: Ta có: 7x-8=713
nên 7x=721
hay x=103
c: Ta có: x-36:18=12
nên x-2=12
hay x=14
d: Ta có: (x-36):18=12
nên x-36=216
hay x=252
a. 124 + (118 – x) = 217
118 - x = 93
- x = - 25
x = 25
b. 7x – 8 = 713
7x =721
x =103
c. x- 36:18 = 12
x- 2 =12
x =14
d. (x- 36):18 = 12
x-36 = 216
x = 252
e. (x-47) -115 = 0
x-47 = 115
x = 162
f. 315 + (146 – x) = 401
146-x =86
-x = -60
x = 60
g. (6x – 39 ) : 3 = 201
6x - 39 = 603
6x = 642
x = 107
h. 23 + 3x = 56 : 53
23 +3x = 125
3x = 102
x=34
Tìm x:
a)5x(x-2)-2x+4=0
b)2x(x+1)-(x-2)^2=6
c)2x^2+7x-9=0
\(a,\Leftrightarrow\left(x-2\right)\left(5x-2\right)=0\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{2}{5}\end{matrix}\right.\\ b,\Leftrightarrow2x^2+2x-x^2+4x-4-6=0\\ \Leftrightarrow x^2+6x-10=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-3+\sqrt{19}\\x=-3-\sqrt{19}\end{matrix}\right.\\ c,\Leftrightarrow2x^2-2x+9x-9=0\\ \Leftrightarrow\left(2x+9\right)\left(x-1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{9}{2}\\x=1\end{matrix}\right.\)
Tìm x:
a) x . 4,25 = 17
b) 116 : x = 14,5
c) 15 . x = 8
d) 729 : x = 36
\(a,x.4,25=7\\ \Rightarrow x=7:4,25\\ \Rightarrow x=\dfrac{28}{17}\\ b,116:x=14,5\\ \Rightarrow x=116:14,5\\ \Rightarrow x=8\\ c,15.x=8\\ \Rightarrow x=\dfrac{8}{15}\\ c,729:x=36\\ \Rightarrow x=729:36\\ \Rightarrow x=20,25\)
Tìm x:
a) x . 4,25 = 17
x = 17 : 4,25
x = 4
b) 116 : x = 14,5
x = 116 : 14,5
x = 8
c) 15 . x = 8
x = 8 : 15
x = 0.53333333333
d) 729 : x = 36
x = 729 : 36
x = 20.25
Giải PT:
a) √ x-5=3
b) √ x-10=-2
c) √ 2x-1=√ 5
d) √ 4-5x=12
e)√ 49(1-2x+x^2)-35=0
f) √ x^2-9-5√ x+3=0a: =>x-5=9
=>x=14
b: căn x-10=-2
=>\(x\in\varnothing\)
c: căn 2x-1=căn 5
=>2x-1=5
=>2x=6
=>x=3
d: căn 4-5x=12
=>4-5x=144
=>5x=-140
=>x=-28
e: =>7|x-1|=35
=>|x-1|=5
=>x-1=5 hoặc x-1=-5
=>x=6 hoặc x=-4
f: =>\(\sqrt{x+3}\left(\sqrt{x-3}-5\right)=0\)
=>x+3=0 hoặc x-3=25
=>x=28 hoặc x=-3
Tìm x:
a) 1 = (2x + 0,5)600
b) (x - 0,125)2 = 0,25
c) (x - 3)11 = (x - 3)41
a) \(1=\left(2x+0,5\right)^{600}\)
\(\Rightarrow1^{600}=\left(2x+0,5\right)^{600}\)
\(\Rightarrow\left[{}\begin{matrix}2x+0,5=1\\2x+0,5=-1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}2x=0,5\\2x=-1,5\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0,25\\x=-0,75\end{matrix}\right.\)
b) \(\left(x-0,125\right)^2=0,25\)
\(\Rightarrow\left(x-0,125\right)^2=0,5^2\)
\(\Rightarrow\left[{}\begin{matrix}x-0,125=0,5\\x-0,125=-0,5\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0,625\\x=-0,375\end{matrix}\right.\)
c) \(\left(x-3\right)^{11}=\left(x-3\right)^{41}\)
\(\Rightarrow\left(x-3\right)^{11}-\left(x-3\right)^{41}=0\)
\(\Rightarrow\left(x-3\right)^{11}\left[1-\left(x-3\right)^{30}\right]=0\)
\(\Rightarrow\left[{}\begin{matrix}\left(x-3\right)^{11}=0\\\left(x-3\right)^{30}=1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x-3=0\\x-3=1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=4\end{matrix}\right.\)
`@` `\text {Ans}`
`\downarrow`
`a)`
`1 = (2x + 0,5)^600`
`=> (2x+0,5)^600 = (+-1)^600`
`=> \text {TH1: } 2x + 0,5 = 1`
`=> 2x = 1 - 0,5`
`=> 2x = 0,5`
`=> x = 0,5 \div 2`
`=> x = 0,25`
`\text {TH2: } 2x + 0,5 = -1`
`=> 2x = -1 - 0,5`
`=> 2x = -1,5`
`=> x = -1,5 \div 2`
`=> x = -0,75`
Vậy, `x \in {-0,75; 0,25}.`
`b)`
`(x - 0,125)^2 = 0,25`
`=> (x - 0,125)^2 = (+-0,5)^2`
`=> `\(\left[{}\begin{matrix}x-0,125=0,5\\x-0,125=-0,5\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=0,5+0,125\\x=-0,5+0,125\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=0,625\\x=-0,375\end{matrix}\right.\)
Vậy, `x \in {-0,375; 0,625}.`
`c)`
`(x - 3)^11 = (x - 3)^41`
`=> (x - 3)^11 - (x - 3)^41 = 0`
`=> (x - 3)^11 * [ 1 - (x - 3)^30] = 0`
`=>`\(\left[{}\begin{matrix}\left(x-3\right)^{11}=0\\1-\left(x-3\right)^{30}=0\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x-3=0\\\left(x-3\right)^{30}=1\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=3\\x-3=1\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=3\\x=4\end{matrix}\right.\)
Vậy, `x \in {3; 4}.`
a, 1=(2x+0,5)600
=>1600=(2x+0,5)600
=>1=2x+0,5
=>2x+0,5=1
=> 2x= 1+0,5
=>2x= 1,5
=:>x= 1,5:2
=>x=0,75
b, (x-0,125)2=0,25
=>(x-0,125)2=(0,5)2
=>x-0,125=0,5
=>x=0,5 +0,125
=>x= 0,625
c, (x-3)11=(x-3)41
(x-3)11 -(x-3)41=0
(x-3)11-(x-3)11 .(x-3)30=0
(x-3)11.[1-(x-3)30 ]=0
(x-3)11.(4-x)30=0
(x-3)11=0 hoặc (4-x)30=0
(x-3)11=0 ( 4-x)30=0
x-3=0 4-x=0
x=0+3 x=4-0
x=3 x=4
vậy xϵ{3,4}