1. | x^3 -8| > 2-x
2. | x^2 -3x +2| >= | x^2 +3x +2|
3. | (x^2 -4x)/x^2 + x+2| <=1
4. | ( x^2-5x+4)/ x^2-4 | <= 1
5. | 1-2/x^2| >= x^2
6. | (2-3|x| )/ 1+x) <= 1.
Những câu hỏi liên quan
Bài 1: Tìm x biết a) x^3 - 4x^2 - x + 4= 0 b) x^3 - 3x^2 + 3x + 1=0 c) x^3 + 3x^2 - 4x - 12=0 d) (x-2)^2 - 4x +8 =0
a: \(x^3-4x^2-x+4=0\)
=>\(\left(x^3-4x^2\right)-\left(x-4\right)=0\)
=>\(x^2\left(x-4\right)-\left(x-4\right)=0\)
=>\(\left(x-4\right)\left(x^2-1\right)=0\)
=>\(\left[{}\begin{matrix}x-4=0\\x^2-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x^2=1\end{matrix}\right.\Leftrightarrow x\in\left\{2;1;-1\right\}\)
b: Sửa đề: \(x^3+3x^2+3x+1=0\)
=>\(x^3+3\cdot x^2\cdot1+3\cdot x\cdot1^2+1^3=0\)
=>\(\left(x+1\right)^3=0\)
=>x+1=0
=>x=-1
c: \(x^3+3x^2-4x-12=0\)
=>\(\left(x^3+3x^2\right)-\left(4x+12\right)=0\)
=>\(x^2\cdot\left(x+3\right)-4\left(x+3\right)=0\)
=>\(\left(x+3\right)\left(x^2-4\right)=0\)
=>\(\left(x+3\right)\left(x-2\right)\left(x+2\right)=0\)
=>\(\left[{}\begin{matrix}x+3=0\\x-2=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=2\\x=-2\end{matrix}\right.\)
d: \(\left(x-2\right)^2-4x+8=0\)
=>\(\left(x-2\right)^2-\left(4x-8\right)=0\)
=>\(\left(x-2\right)^2-4\left(x-2\right)=0\)
=>\(\left(x-2\right)\left(x-2-4\right)=0\)
=>(x-2)(x-6)=0
=>\(\left[{}\begin{matrix}x-2=0\\x-6=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=6\end{matrix}\right.\)
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BT: Giải các phương trình
a) 4x+5/x-1 + 2x-1/x+1 = 6
b)x+2/x-3 + x-2/x+3 = 2(x^2 + 6)/x^2-9
c)1/x-1 + 3 = 3x-2/x+2
d) 8/x+1 + 1/x-1 = 9/x
e)(4x+1)(3x+7/3-5x + 1)= (x-4)(3x+7/5x-3 - 1)
f) (x^2 + 3x + 1)(4x-3/3x+1 + 2)= (4x+7)(4x-3/3x+1 + 2)
Mọi người giúp mìnnn vớiii
Chủ đề 1: Thực hiện phép tính1) (2x+3).(2x-3)-4x.(x+5) 2) 6/x2 - 9 + 5/x-3 + 1/x+3 3)5x.(x-3)+(x-2)24) 4x/x+2 - 3x/x-2 + 12x/ x2 - 45) x(x+2) - ( x-3)(x+3)6) 1/3x-2 + -4/3+2 + 6-3x/9x2 - 47)2x.(3x-1)+(x+2)2 8) 6/x+3 - 6/x-3 + 9x+9/x2 - 99) (2x - 5)2 - x(4x-13)10) x-1/x + 4/x+8 + 8/x2 + 8x11) (2x+1)2 + (x-5)(x+5)-x(5x+7)12) 6/x2-9 + 5/x-3 + 1/x+313) 6x(5x-2)+(2x+3)214) x/x-2 + -2/x-3 + x(1-x)/x2-915) (x-2)2-x(x+5)16) 2/x+3 + 3/x-3 + -6/x2-917) 3x(x-3) + (3x-1)2
Đọc tiếp
Chủ đề 1: Thực hiện phép tính
1) (2x+3).(2x-3)-4x.(x+5)
2) 6/x2 - 9 + 5/x-3 + 1/x+3
3)5x.(x-3)+(x-2)2
4) 4x/x+2 - 3x/x-2 + 12x/ x2 - 4
5) x(x+2) - ( x-3)(x+3)
6) 1/3x-2 + -4/3+2 + 6-3x/9x2 - 4
7)2x.(3x-1)+(x+2)2
8) 6/x+3 - 6/x-3 + 9x+9/x2 - 9
9) (2x - 5)2 - x(4x-13)
10) x-1/x + 4/x+8 + 8/x2 + 8x
11) (2x+1)2 + (x-5)(x+5)-x(5x+7)
12) 6/x2-9 + 5/x-3 + 1/x+3
13) 6x(5x-2)+(2x+3)2
14) x/x-2 + -2/x-3 + x(1-x)/x2-9
15) (x-2)2-x(x+5)
16) 2/x+3 + 3/x-3 + -6/x2-9
17) 3x(x-3) + (3x-1)2
\(\left(2x+3\right)\left(2x-3\right)-4x\left(x+5\right)=4x^2-9-4x^2-20x=-20x-9\)
\(5x\left(x-3\right)+\left(x-2\right)^2=5x^2-15x+x^2-4x+4=6x^2-19x+4\)
\(x\left(x+2\right)-\left(x-3\right)\left(x+3\right)=x^2+2x-\left(x^2-9\right)=x^2+2x-x^2+9=2x+9\)
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Tìm x biết
1.(x+3)2-(x+2).(x-2)=4x+17
2.(2x+1)2-(4x-1).(x-3)-15=0
3.(2x+3).(x-1)+(2x-3).(1-x)=0
4.2(5x-8)-3(4x-5)=4(3x-4)+11
5.(3x-1).(2x-7)-(1-3x).(6x-5)=0
1: Ta có: \(\left(x+3\right)^2-\left(x+2\right)\left(x-2\right)=4x+17\)
\(\Leftrightarrow x^2+6x+9-x^2+4-4x=17\)
\(\Leftrightarrow x=2\)
3: Ta có: \(\left(2x+3\right)\left(x-1\right)+\left(2x-3\right)\left(1-x\right)=0\)
\(\Leftrightarrow2x^2-2x+3x-3+2x-2x^2-3+3x=0\)
\(\Leftrightarrow6x=6\)
hay x=1
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Timf `x`:
`(x - 2)/3 = (x + 1)/4`
`(x - 2) . 4 = (x + 1) . 3`
`<=> 4x - 8 = 3x + 3`
`<=> 4x - 3x = 3 + 8`
`<=> (4 - 3)x = 11`
`=> x = 11`
`(x - 2)/3 = (x + 1)/4`
`(x - 2) . 4 = (x + 1) . 3`
`<=> 4x - 8 = 3x + 3`
`<=> 4x - 3x = 3 + 8`
`<=> (4 - 3)x = 11`
`=> x = 11`
`=>` `x = 11`
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Xem thêm câu trả lời
giải pt
a 2(x+3)(x-4)=(2x-1)(x+2)-27
b (3x+2)(x-1)-3(x+1)(x-2)=4
c (x+2)(x^2 -2x+4)-x(x-3)(x+3)=26
d (3x+2)(3x-2)-(3x-4)^2=28
e 5(x+3)^2-5(x-4)(x+8)=3x
f 2x(x+2)^2-8x^2=2(x-2)(x^2+2x+4)
g (2x-1)(4x^2+2x+1)-4x(2x^2-3)=23
h x(x-2)(x+2)-(x-3)(x^2+3x+9)+1=0
i x(x^2+x+1)-(x-1)(x+1)x=x^2+2
a, \(2\left(x+3\right)\left(x-4\right)=\left(2x-1\right)\left(x+2\right)-27\)
\(\Leftrightarrow2\left(x^2-4x+3x-12\right)=2x^2+4x-x-2-27\)
\(\Leftrightarrow2x^2-2x-24=2x^2+3x-29\Leftrightarrow-5x+5=0\Leftrightarrow x=1\)
b, \(\left(x+2\right)\left(x^2-2x+4\right)-x\left(x-3\right)\left(x+3\right)=26\)
\(\Leftrightarrow x^3-8-x\left(x^2-9\right)=26\Leftrightarrow-8+9x=26\)
\(\Leftrightarrow9x=18\Leftrightarrow x=2\)
làm phép chia :
a) (x^4 -2x^3 + 2x -1) : (x^2 - 1)
b) (x^3 -8) : (x^2 + 2x +4)
c) (x^6 - 2x^5 + 2x^4 + 6x^3 - 4x^2)n: 6x^2
d) (-2x^5 + 3x^2 - 4x^3) :2x^2
e) (15x^3 - 10x^2 + x - 2) : (x - 2)
f) (2x^4 - 3x^3 - 3x^2 + 6x - 2) : (x^2 - 2)
b: =x-2
d: \(=-x^3+\dfrac{3}{2}-2x\)
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bài 1 :1)2/x-1 + 2x+3/x^2+x+1(2x+1)(2x-1)/x^3-12)x^3-(x+1)^3/(4x+3)(x-5)7x-1/4x+3 - x/x-5 (x-1/9)3)12/1-9x^21-3x/1+3x - 1+3x/1-3x (x-1)4)x+5/x-1x+1/x-3 - 8/x^2-4x+35)1/x-1 + 2x/x+3-1 (x0,-1/3)6)1/3y^2-10y+36y/9y^2-1 + 2/1-3y (y1)7)24/x^2-2x+43x/x+2 + 72/x^3+8 (x2)8)1/x^2+9x+20 +1/x^2+11x+30 +1/x^2+13x+421/18 (-13,2)9)x+4/2x^2-5x+2 + x+1/2x^2-7x+32x+5/2x^2-7x+3 (x4)10)12x/x-4 - 3x^2/x+4384/x^2-16bài 2:tìm giá trị lớn nhất và nhỏ nhất của các đa thức sauAx^2+4x+5 B-x^2-2x+2 C x^2+2x+3 ...
Đọc tiếp
bài 1 :1)2/x-1 + 2x+3/x^2+x+1=(2x+1)(2x-1)/x^3-1
2)x^3-(x+1)^3/(4x+3)(x-5)=7x-1/4x+3 - x/x-5 (x=-1/9)
3)12/1-9x^2=1-3x/1+3x - 1+3x/1-3x (x=-1)
4)x+5/x-1=x+1/x-3 - 8/x^2-4x+3
5)1/x-1 + 2x/x+3=-1 (x=0,-1/3)
6)1/3y^2-10y+3=6y/9y^2-1 + 2/1-3y (y=1)
7)24/x^2-2x+4=3x/x+2 + 72/x^3+8 (x=2)
8)1/x^2+9x+20 +1/x^2+11x+30 +1/x^2+13x+42=1/18 (-13,2)
9)x+4/2x^2-5x+2 + x+1/2x^2-7x+3=2x+5/2x^2-7x+3 (x=4)
10)12x/x-4 - 3x^2/x+4=384/x^2-16
bài 2:
tìm giá trị lớn nhất và nhỏ nhất của các đa thức sau
A=x^2+4x+5 B=-x^2-2x+2 C= x^2+2x+3 D=-x^2+4x+2000
E=10x-4x^2-23 F=1/x^2-2x+3 G=3x^2+3x+5/x^2+x+1 H=x^2+x+1/x^2-x+1
O=5x^2+8xy+5y^2 P=42-x/x-15
bài 3: so sánh A và B biết : A=2003.2005 và 2004^2
8 tháng 9 2021 lúc 14:22
Bài 4: Tìm x, biết:
a) 3(2x – 3) + 2(2 – x) = –3 ; b) x(5 – 2x) + 2x(x – 1) = 13 ;
c) 5x(x – 1) – (x + 2)(5x – 7) = 6 ; d) 3x(2x + 3) – (2x + 5)(3x – 2) = 8 ;
e) 2(5x – 8) – 3(4x – 5) = 4(3x – 4) + 11; f) 2x(6x – 2x 2 ) + 3x 2 (x – 4) = 8.
\(a,3\left(2x-3\right)+2\left(2-x\right)=-3\\ \Leftrightarrow6x-9+4-2x=-3\\ \Leftrightarrow4x=2\\ \Leftrightarrow x=\dfrac{1}{2}\\ b,x\left(5-2x\right)+2x\left(x-1\right)=13\\ \Leftrightarrow5x-2x^2+2x^2-2x=13\\ \Leftrightarrow3x=13\\ \Leftrightarrow x=\dfrac{13}{3}\\ c,5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\\ \Leftrightarrow5x^2-5x-5x^2-3x+14=6\\ \Leftrightarrow-8x=-8\\ \Leftrightarrow x=1\\ d,3x\left(2x+3\right)-\left(2x+5\right)\left(3x-2\right)=8\\ \Leftrightarrow6x^2+9x-6x^2-11x+10=8\\ \Leftrightarrow-2x=-2\\ \Leftrightarrow x=1\)
\(e,2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\\ \Leftrightarrow10x-16-12x+15=12x-16+11\\ \Leftrightarrow-14x=-4\\ \Leftrightarrow x=\dfrac{2}{7}\\ f,2x\left(6x-2x^2\right)+3x^2\left(x-4\right)=8\\ \Leftrightarrow12x^2-4x^3+3x^3-12x^2=8\\ \Leftrightarrow-x^3-8=0\\ \Leftrightarrow-\left(x^3+8\right)=0\\ \Leftrightarrow-\left(x+2\right)\left(x^2-2x+4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-2\\x\in\varnothing\left(x^2-2x+4=\left(x-1\right)^2+3>0\right)\end{matrix}\right.\)
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Bài 4:
a: Ta có: \(3\left(2x-3\right)-2\left(x-2\right)=-3\)
\(\Leftrightarrow6x-9-2x+4=-3\)
\(\Leftrightarrow4x=2\)
hay \(x=\dfrac{1}{2}\)
b: Ta có: \(x\left(5-2x\right)+2x\left(x-1\right)=13\)
\(\Leftrightarrow5x-2x^2+2x^2-2x=13\)
\(\Leftrightarrow3x=13\)
hay \(x=\dfrac{13}{3}\)
c: Ta có: \(5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\)
\(\Leftrightarrow5x^2-5x-5x^2+7x-10x+14=6\)
\(\Leftrightarrow-8x=-8\)
hay x=1
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a/ \(3\left(2x-3\right)+2\left(2-x\right)=-3\)
\(\Leftrightarrow6x-9+4-2x=-3\)
\(\Leftrightarrow4x=2\)
\(\Leftrightarrow x=\dfrac{1}{2}\)
Vậy: \(x=\dfrac{1}{2}\)
===========
b/ \(x\left(5-2x\right)+2x\left(x-1\right)=13\)
\(\Leftrightarrow5x-2x^2+2x^2-2x=13\)
\(\Leftrightarrow3x=13\)
\(\Leftrightarrow x=\dfrac{13}{3}\)
Vậy: \(x=\dfrac{13}{3}\)
==========
c/ \(5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\)
\(\Leftrightarrow5x^2-5x-5x^2+7x-10x+14=6\)
\(\Leftrightarrow-8x=-8\)
\(\Leftrightarrow x=1\)
Vậy: \(x=1\)
==========
d/ \(3x\left(2x+3\right)-\left(2x+5\right)\left(3x-2\right)=8\)
\(\Leftrightarrow6x^2+9x-6x^2+4x-15x+10=8\)
\(\Leftrightarrow-2x=-2\)
\(\Leftrightarrow x=1\)
Vậy: \(x=1\)
==========
e/ \(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)
\(\Leftrightarrow10x-16-12x+15=12x-16+11\)
\(\Leftrightarrow-14x=-4\)
\(\Leftrightarrow x=\dfrac{2}{7}\)
Vậy: \(x=\dfrac{2}{7}\)
==========
f/ \(2x\left(6x-2x^2\right)+3x^2\left(x-4\right)=8\)
\(\Leftrightarrow12x^2-4x^3+3x^3-12x^2=8\)
\(\Leftrightarrow-x^3=8\)
\(\Leftrightarrow x=-2\)
Vậy: \(x=-2\)
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`c)(2x-1)^{2}+(1-x).3x<=(x+2)^{2}`
`<=>>4x^{2}-4x+1+3x-3x^{2}<=x^{2}+4x+4`
`<=>x^{2}-x+1<=x^{2}+4x+4`
`<=>4x+x>=1-4`
`<=>5x>=-3`
`<=>x>=-3/5`
thứ nhất bn đăng sai môn
thứ hai bn giải r đăng lmj :???
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