tìm x:
a) 2x : 25 = 4.
b) 4(x + 41) = 400
c) (x + 7) – 25 = 13
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1 tháng 10 2021 lúc 21:37
Bài3:Tìm x:a) 71 – (33 + x) 26b) (x + 73) – 26 76c) 45 – (x + 9) 6d) 89 – (73 – x) 20e) 4(x + 41) 400f) 11(x – 9) 77g) (x + 7) – 25 13h) 198 – (x + 4) 120i) 5(x – 9) 350j) 2x – 49 5.32k) 25 + 3(x – 8) 106l) 32(x + 4) – 52 5.22m) 200 – (2x + 6) 43n) 2(x- 51) 2.23 + 20o) 450 : (x – 19) 50p) 4(x – 3) 72 – 110q) 156 – (x+ 61) 82r) (x-35) -120 0
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Bài3:Tìm x:
a) 71 – (33 + x) = 26 b) (x + 73) – 26 = 76 c) 45 – (x + 9) = 6 d) 89 – (73 – x) = 20 e) 4(x + 41) = 400 f) 11(x – 9) = 77 | g) (x + 7) – 25 = 13 h) 198 – (x + 4) = 120 i) 5(x – 9) = 350 j) 2x – 49 = 5.32 k) 25 + 3(x – 8) = 106 l) 32(x + 4) – 52 = 5.22 | m) 200 – (2x + 6) = 43 n) 2(x- 51) = 2.23 + 20 o) 450 : (x – 19) = 50 p) 4(x – 3) = 72 – 110 q) 156 – (x+ 61) = 82 r) (x-35) -120 = 0 |
a: Ta có: \(71-\left(x+33\right)=26\)
\(\Leftrightarrow x+33=45\)
hay x=12
b: Ta có: \(\left(x+73\right)-26=76\)
\(\Leftrightarrow x+73=102\)
hay x=29
c: Ta có: \(45-\left(x+9\right)=6\)
\(\Leftrightarrow x+9=39\)
hay x=30
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a) 71 - ( 33 + x ) = 26
(33 + x ) = 71 -26
33 + x = 45
x = 45 - 33 = 12
b) ( x + 73 ) - 26 = 76
( x + 73 ) = 102
x = 102 - 73 = 29
c) 45 - ( x + 9 ) = 6
( x + 9 ) = 45 - 6 = 39
x = 39 - 9 = 30
d) 89 - ( 73 - x ) = 20
73 - x = 89 - 20
73 - x = 69
x = 73 - 69 = 4
e) 4(x+41) = 400
x + 41 = 400 : 4 = 100
x = 100 - 41 = 59
f) 11(x-9 ) = 77
x - 9 = 77 : 11 = 7
x = 7 + 9 = 16
g) x + 7 = 25 + 13 = 38
x = 38 - 7 = 31
h) x + 4 = 198 - 120 = 78
x = 78 - 4 = 74
i) x - 9 = 350 : 5 = 70
x = 70 + 9 = 79
j) 2x - 49 = 5 . 9 = 45
2x = 45 + 49 = 94
x = 94 : 2 = 47
k) 25 + 3( x - 8 ) = 106
3(x-8 ) = 106 - 25 = 81
x - 8 = 81 : 3 = 27
x = 27 +8= 35
l) 9( x + 4 ) - 25 = 20
9( x + 4 ) = 20 + 25 = 45
x + 4 =45 : 9 = 5
x = 5 - 4 = 1
m) 200 - ( 2x + 6 ) = 64
2x + 6 = 200 - 64 = 136
2x = 136 - 6 = 130
x = 130 : 2 = 65
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n) 2(x-51) = 16 + 20 = 36
x - 51 = 36 : 2 = 13
x = 13 + 51 = 64
o) 450 : ( x - 19 ) = 50
x - 19 = 450 : 50 = 9
x = 19 + 9 = 28
p)4(x-3) = 49 - 1 = 48
x - 3 = 48 : 4 = 12
x + 15
q) 156 - ( x+61 ) = 82
x + 61 = 156 - 82 = 74
x = 74 - 61 = 13
r) ( x - 35 ) - 120 = 0
x - 35 = 120
x = 120 + 35 = 155
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20 tháng 9 2023 lúc 18:21
Tim x:
a) \(\dfrac{13+x}{20}=\dfrac{3}{4}\)
b) \(\dfrac{23-x}{25}=\dfrac{4}{5}\)
`(13+x)/20 = 3/4`
`(13+x) xx4=3xx20`
`(13+x)xx4=60`
`13+x=60:4`
`13+x=15`
`x=15-13`
`x=2`
__
`(23-x)/25 =4/5`
`(23-x)xx5=4xx25`
`(23-x)xx5=100`
`23-x=100:5`
`23-x=20`
`x=23-20`
`x=3`
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Bài 1: Tìm x:a) x - 2 + 7 = 1 . 3 . -9 b) 4 . x - 1 = (-5) 5 12 2 4 16 9 2 9c) -2 . x + 5 = 7 d) 2 . x : 7 . 1 = 29 3 8 12 5 3 8 15Bài 2: Tính:a) 2 + 1 . 4 b) 0,8 : [ 4 . 1,25] - [ 0,64 - 1 ] 5 7 5 25--------------------- 8 - 1 : 3 2 5 c) 8 : [ 7 - 12 ] d) ( 1,08 - 2 ) : 4 + ( 59 - 13 ). 36 9 2 7 25 7 9 4 17----------------------- [ 5 - 1 ] : 4
Tìm X:
a)(x-4)(x+4)=9
b)x2-4x+4-(5x-2)2=0
c)4x2+4+1-x2-10x-25=0
d)(x2+x+7)(x2+x-7)=(x2+x)2-7x
a)
⇔ \(x^2-16=9\)
⇔ \(x^2=25\)
⇔ \(x=\pm5\)
b)
⇔ \(x^2-4x+4-25x^2+20x-4=0\)
⇔ \(16x-24x^2=0\)
⇔ \(8x\left(2-3x\right)=0\)
⇒ \(\left[{}\begin{matrix}x=0\\2-3x=0\end{matrix}\right.\) ⇔ \(\left[{}\begin{matrix}x=0\\x=\dfrac{2}{3}\end{matrix}\right.\)
Vậy \(x=0\) hoặc \(x=\dfrac{2}{3}\)
c)
⇔ \(3x^2-10x-20=0\)
⇔ \(x^2-2.x.\dfrac{5}{3}+\dfrac{25}{9}-\dfrac{205}{9}=0\)
⇔ \(\left(x-\dfrac{5}{3}\right)^2=\dfrac{205}{9}\)
⇒ \(\left[{}\begin{matrix}x-\dfrac{5}{3}=\sqrt{\dfrac{205}{9}}\\x-\dfrac{5}{3}=-\sqrt{\dfrac{205}{9}}\end{matrix}\right.\) ⇔ \(\left[{}\begin{matrix}x=\dfrac{\sqrt{\text{205}}}{\text{3}}+\dfrac{5}{3}\\x=-\dfrac{\sqrt{\text{205}}}{\text{3}}+\dfrac{5}{3}\end{matrix}\right.\) ⇔ \(\left[{}\begin{matrix}x=\dfrac{15+\text{9}\sqrt{\text{205}}}{\text{9}}\\\text{x}=-\dfrac{15+\text{9}\sqrt{\text{205}}}{\text{9}}\end{matrix}\right.\)
Vậy...
d)
⇔ \(\left(x^2+x\right)^2-49=\left(x^2+x\right)^2-7x\)
⇔ 7x = 49
⇔ x=7
Vậy...
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Bài 1 : Tìm x thuộc Z, biết :
a) ( 7-x ) - ( 25+7 ) = -25
b) 4 - ( 7-x ) = x - ( 13-4 )
c) -20 + 8.( x+3 ) + 2x = 5^2 . 4 + 5x - ( -19 )
GIÚP MÌNH VỚIIIIIII
21 tháng 7 2021 lúc 20:59
Tìm x:
a)\(\dfrac{1}{3}\sqrt{x-1}+2\sqrt{4x-4}-12\sqrt{\dfrac{x-1}{25}}=\dfrac{29}{15}\)
b)\(\dfrac{3x-2}{\sqrt{x-1}}-\sqrt{x+1}=\sqrt{2x-3}\)
Tìm x:
a, 4.( x + 41 ) = 7
b, 4. ( x-3 ) = 7 mũ 2 - 1 mũ 10
a. 4.(x+41) = 7
x + 41 = 7 : 4 = 1,75
x = 1,75 - 41 = -39,25
b. 4.(x-3) = 72 - 110 = 49 - 1 = 48
x - 3 = 48 : 4 = 12
x = 12 + 3 = 15
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Tìm x:
a, 4.( x + 41 ) = 400
b, 4. ( x-3 ) = 7 mũ 2 - 1 mũ 10
a) \(4\left(x+41\right)=400\)
\(\Rightarrow x+41=400:4\)
\(\Rightarrow x+41=100\)
\(\Rightarrow x=100-41\)
\(\Rightarrow x=59\)
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a/ \(4.\left(x+41\right)=400\)
\(x+41=\dfrac{400}{4}=100\)
\(\Rightarrow x=59\)
b/ \(4.\left(x-3\right)=7^2-1^{10}\)
\(4.\left(x-3\right)=49-1\)
\(4.\left(x-3\right)=48\)
\(x-3=\dfrac{48}{3}=16\)
\(\Rightarrow x=19\)
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a ) 4 . ( x + 41 ) = 400
x + 41 = 400 : 4
x + 41 = 100
x = 100 - 41
x = 59
b ) 4 . ( x - 3 ) = 72- 110
4 . ( x - 3 ) = 49 - 1
4 . ( x - 3 ) = 48
x - 3 = 48 : 4
x - 3 = 12
x = 12 + 3
x = 15
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