a)234+(345-x)=500
b)456-(x+23)=326
c)(5.x-15):5=0
d)84-4.(2.x+1)=48
e)(x-76).54=0
f)(x-3).(x+4)=0
g)(x-6).(x-7)=0
h)(x-2).(x-3).(x-5)=0
ai nhanh mk tick cho
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Những câu hỏi liên quan
3 tháng 10 2018
1. 234 + ( 345 - x ) = 500
345 - x = 500 - 234
345 - x = 266
x = 345 - 266
x = 79
2. 456 - ( x + 23 ) = 326
x + 23 = 456 - 326
x + 23 = 130
x = 130 - 23
x = 107
3. ( 567 - x ) . 212 = 605
567 - x = 605 : 212
567 - x = ...
=> Đề sai
4. ( 5 . x - 15 ) : 5 = 0
5 . x - 15 = 0 : 5
5 . x - 15 = 0
5 . x = 0 + 15
5 . x = 15
x = 15 : 5
x = 3
5. 14 x ( x - 7 ) = 210
x - 7 = 210 : 14
x - 7 = 15
x = 15 + 7
x = 22
6. 84 - 4 x ( 2 . x + 1 ) = 48
4 x ( 2 . x + 1 ) = 84 - 48
4 x ( 2 . x + 1 ) = 36
2 . x + 1 = 36 : 4
2 . x + 1 = 9
2 . x = 9 - 1
2 . x = 8
x = 8 : 2
x = 4
LH
3 tháng 10 2018
1. 345 - x = 500 - 234
345-x=266
x=345-266
x=79
2. x+23 =456-326
x+23=130
x=130-23
x=107
4. 5 x X - 15 =5 x0
5xX -15=0
5 x X = 0+15
5x X = 15
X = 15:5
X =3
5 . x-7 = 210 :14
x - 7 =15
x=15+7
x=22
TT
12 tháng 1 2023
\(a,\left(x-1\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-2\end{matrix}\right.\)
\(b,\left(x-2\right)\left(x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x-5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=5\end{matrix}\right.\)
\(c,\left(x+3\right)\left(x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=0\\x-5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=5\end{matrix}\right.\)
\(d,\left(x+\dfrac{1}{2}\right)\left(4x+4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\4x+4=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\4\left(x+1\right)=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=-1\end{matrix}\right.\)
\(e,\left(x-4\right)\left(5x-10\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-4=0\\5x-10=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=2\end{matrix}\right.\)
\(f,\left(2x-1\right)\left(3x+6\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-1=0\\3x+6=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=-2\end{matrix}\right.\)
DD
12 tháng 1 2023
`a,(x-1)(x+2)=0`
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-2\end{matrix}\right.\)
`b,(x -2)(x -5)=0`
\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x-5=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=5\end{matrix}\right.\)
`c,(x +3)(x -5)=0`
\(\Leftrightarrow\left[{}\begin{matrix}x+3=0\\x-5=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=5\end{matrix}\right.\)
`d,(x + 1/2)(4x + 4)=0`
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\4x+4=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\4x=-4\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=-1\end{matrix}\right.\)
`e,(x -4)(5x -10)=0`
\(\Leftrightarrow\left[{}\begin{matrix}x-4=0\\5x-10=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\5x=10\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=2\end{matrix}\right.\)
`f,(2x -1)(3x +6)=0`
\(\Leftrightarrow\left[{}\begin{matrix}2x-1=0\\3x+6=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2x=1\\3x=-6\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=-2\end{matrix}\right.\)
`g,(2,3x -6,9)(0,1x -2)=0`
\(\Leftrightarrow\left[{}\begin{matrix}2,3x-6,9=0\\0,1x-2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2,3x=6,9\\0,1x=2\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=20\end{matrix}\right.\)
8 tháng 7 2017
Bài 1 :
a) ( 257 x 139 - 257 x 39 ) : 100
= 257 x ( 139 - 39 ) : 100
= 257 x 100 : 100
= 257
8 tháng 7 2017
a) ( 257 × 139 – 257 × 39 ) : 100
= [ 257 x ( 139 -39 ) ] : 100
= ( 257 x 100 ) :100
= 25700 :100
=257
b) 5 + 6 + 13 + 17 + .......+ 2017
= ( 5 + 2017 ) + ( 6 + 2016 ) + ( 7 + 2015 ) + ... + ( 1009 + 1013 ) + ( 1010 + 1012 ) + 1011
= 2022 + 2022 + 2022 + ... + 2022 + 2022 + 1011
= 2022 × 1006 + 1011
= 203514
c) 12 × 57 + 57 × 15 + 63 × 57
= 57 × ( 12 + 15 + 63 )
= 57 x 90
= 5130
RH
18 tháng 2 2022
\(a)x^2-9x+20=0 \\<=>(x-4)(x-5)=0 \\<=>x=4\ hoặc\ x=5 \\b)x^2-3x-18=0 \\<=>(x+3)(x-6)=0 \\<=>x=-3\ hoặc\ x=6 \\c)2x^2-9x+9=0 \\<=>(x-3)(2x-3)=0 \\<=>x=3\ hoặc\ x=\dfrac{3}{2}\)
18 tháng 2 2022
d: \(\Leftrightarrow3x^2-6x-2x+4=0\)
=>(x-2)(3x-2)=0
=>x=2 hoặc x=2/3
e: \(\Leftrightarrow3x\left(x^2-2x-3\right)=0\)
=>x(x-3)(x+1)=0
hay \(x\in\left\{0;3;-1\right\}\)
f: \(\Leftrightarrow x^2-5x-2+x=0\)
\(\Leftrightarrow x^2-4x-2=0\)
\(\Leftrightarrow\left(x-2\right)^2=6\)
hay \(x\in\left\{\sqrt{6}+2;-\sqrt{6}+2\right\}\)
T
Giải phương trình
e) x4 -4x3-8x2+8x=0
f) 2x2+3xy+y2=0
g) 2x4-x3-9x2+13x-5=0
h) (x+1)(x+3)(x+5)(x+7)+15=0
1
18 tháng 8 2023
e: =>x(x^3-4x^2-8x+8)=0
=>x[(x^3+8)-4x(x+2)]=0
=>x(x+2)(x^2-2x+4-4x)=0
=>x(x+2)(x^2-6x+4)=0
=>\(x\in\left\{0;-2;3+\sqrt{5};3-\sqrt{5}\right\}\)
g: =>2x^4+5x^3-6x^3-15x^2+6x^2+15x-2x-5=0
=>(2x+5)(x^3-3x^2+3x-1)=0
=>(2x+5)(x-1)^3=0
=>x=1 hoặc x=-5/2
h: =>(x^2+8x+7)(x^2+8x+15)+15=0
=>(x^2+8x)^2+22(x^2+8x)+120=0
=>(x^2+8x+10)(x^2+8x+12)=0
=>(x^2+8x+10)(x+2)(x+6)=0
=>\(x\in\left\{-2;-6;-4+\sqrt{6};-4-\sqrt{6}\right\}\)
DT
18 tháng 2 2022
a, \(\Leftrightarrow\left(9x^2-4\right)\left(x+1\right)-\left(3x+2\right)\left(x-1\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(\left(9x^2-4\right)-\left(\left(3x+2\right)\left(x-1\right)\right)\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(9x^2-4-\left(3x^2-x-2\right)\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(9x^2-4-3x^2+x+2\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(3x^2+x-2\right)=0\)
\(\Leftrightarrow\left(x+1\right)=0;3x^2+x-2=0\)
=> x=-1
với \(3x^2+x-2=0\)
ta sử dụng công thức bậc 2 suy ra : \(x=\dfrac{2}{3};x=-1\)
Vậy ghiệm của pt trên \(S\in\left\{-1;\dfrac{2}{3}\right\}\)
18 tháng 2 2022
b: \(\Leftrightarrow x^2-2x+1-1+x^2=x+3-x^2-3x\)
\(\Leftrightarrow2x^2-2x=-x^2-2x+3\)
\(\Leftrightarrow3x^2=3\)
hay \(x\in\left\{1;-1\right\}\)
c: \(\Leftrightarrow\left(x-1\right)\left(x+1\right)\left(x+2\right)\left(x-3\right)-\left(x-1\right)\left(x-2\right)\left(x+2\right)\left(x+5\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+2\right)\left[\left(x+1\right)\left(x-3\right)-\left(x-2\right)\left(x+5\right)\right]=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+2\right)\left(x^2-2x-3-x^2-3x+10\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+2\right)\left(-5x+7\right)=0\)
hay \(x\in\left\{1;-2;\dfrac{7}{5}\right\}\)
HV
8
S
22 tháng 3 2021
a, 3x - 7 = 0
<=> 3x = 7
<=> x = 7/3
b, 8 - 5x = 0
<=> -5x = -8
<=> x = 8/5
c, 3x - 2 = 5x + 8
<=> -2x = 10
<=> x = -5
22 tháng 3 2021
e) Ta có: \(\left(5x+1\right)\left(x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}5x+1=0\\x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}5x=-1\\x=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{5}\\x=3\end{matrix}\right.\)
Vậy: \(S=\left\{-\dfrac{1}{5};3\right\}\)
a) \(234+\left(345-x\right)=500\)
\(345-x=500-234\)
\(345-x=266\)
\(x=79\)
vay \(x=79\)
b) \(456-\left(x+23\right)=326\)
\(x+23=456-326\)
\(x+23=130\)
\(x=107\)
vay \(x=107\)
c) \(\left(5x-15\right):5=0\)
\(5x-15=0\)
\(5x=15\)
\(x=3\)
vay \(x=3\)
d) \(84-4\left(2x+1\right)=48\)
\(8x+4=84-48\)
\(8x+4=36\)
\(8x=32\)
\(x=4\)
vay \(x=4\)
e) \(\left(x-76\right).54=0\)
\(x-76=0\)
\(x=76\)
vay \(x=76\)
f) \(\left(x-3\right)\left(x+4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\x+4=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=3\\x=-4\end{cases}}\)
vay \(\orbr{\begin{cases}x=3\\x=-4\end{cases}}\)
g) \(\left(x-6\right)\left(x-7\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-6=0\\x-7=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=6\\x=7\end{cases}}\)
vay \(\orbr{\begin{cases}x=6\\x=7\end{cases}}\)
h) \(\left(x-2\right)\left(x-3\right)\left(x-5\right)=0\)
\(\Rightarrow x-2=0\Rightarrow x=2\)hoac \(\orbr{\begin{cases}x-3=0\\x-5=0\end{cases}\Rightarrow}\orbr{\begin{cases}x=3\\x=5\end{cases}}\)
vay \(x=2\)hoac \(\orbr{\begin{cases}x=3\\x=5\end{cases}}\)
những bài này dễ mà bn