Tìm x, biết: \(\left|4x^2+\left|3x+2\right|\right|=4x^2+2x+3\)
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10 tháng 8 2021 lúc 18:55
Tìm \(x\) biết:
\(\left(2x-1\right)^3\)\(-2x\left(4x^2-3x\right)=5\)
\(\Leftrightarrow\left(8x^3-12x^2+6x-1\right)-\left(8x^3-6x^2\right)=5\)
\(\Leftrightarrow8x^3-12x^2+6x-1-8x^3+6x^2=5\)
\(\Leftrightarrow6x^2-6x+6=0\)
\(\Leftrightarrow x^2-x+1=0\)
\(\Leftrightarrow\left(x-\dfrac{1}{2}\right)^2+\dfrac{3}{4}=0\)
Do \(\left(x-\dfrac{1}{2}\right)^2\ge0;\forall x\Rightarrow\left(x-\dfrac{1}{2}\right)^2+\dfrac{3}{4}>0;\forall x\)
\(\Rightarrow\) Phương trình vô nghiệm
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Ta có: \(\left(2x-1\right)^3-2x\left(4x^2-3x\right)=5\)
\(\Leftrightarrow8x^3-6x^2+12x-1-8x^3+6x^2=5\)
\(\Leftrightarrow12x=6\)
hay \(x=\dfrac{1}{2}\)
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Tìm x: \(\left(x+3\right)^3-x\left(3x+1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)-3x^2=54\)
\(\left(x+3\right)^3-x\left(3x+1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)-3x^2=54\)
\(\Leftrightarrow x^3+9x^2+27x+27-x\left(9x^2+6x+1\right)+8x^3+1-3x^2=54\)
=>\(9x^3+6x^2+27x+28-9x^3-6x^2-x=54\)
=>26x+28=54
=>26x=26
=>x=26/26=1
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Tìm x biết
a) \(\left(x+3\right)^3-x\left(3x+1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)-3x^2=54\)
Tìm x,biết
\(\left(x+3\right)^3-x\left(3x+1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)-3x^2=42\) 42
tìm x, biết:
\(a,-4x\left(x-7\right)+4x\left(x^2-5\right)\)\(=28x^2-13\)
\(b,\left(4x^2-5x\right)\left(3x+2\right)-7x\left(x+5\right)\))\(=\left(-4+x\right)\left(-2x+3\right)+12x^2+2x^2\)
a) -4x(x - 7) + 4x(x2 - 5) = 28x2 - 13
=> -4x2 + 28x + 4x2 - 20x = 28x2 - 13
=> (-4x2 + 4x2) + (28x - 20x) = 28x2 - 13
=> 8x = 28x2 - 13
=> 8x - 28x2 + 13 = 0
=> phương trình vô nghiệm
b) (4x2 - 5x)(3x + 2) - 7x(x + 5) = (-4 + x)(-2x - 3) + 12x2 + 2x2
=> 4x2(3x + 2) - 5x(3x + 2) - 7x2 - 35x = -4(-2x - 3) + x(-2x - 3) + 14x2
=> 12x3 + 8x2 - 15x2 - 10x - 7x2 - 35x = 8x + 12 - 2x2 - 3x + 14x2
=> 12x3 + (8x2 - 15x2 - 7x2) + (-10x - 35x) = (8x - 3x) + 12 + (-2x2 + 14x2)
=> 12x3 - 14x2 - 45x = 5x + 12 + 12x2
=> 12x3 - 14x2 - 45x - 5x - 12 - 12x2 = 0
=> 12x3 + (-14x2 - 12x2) + (-45x - 5x) - 12 = 0
=> 12x3 - 26x2 - 50x - 12 = 0
Làm nốt
Cái câu b sửa cái đề lại nhé dấu " = " ở chỗ (-2x = 3) là gì vậy?
a, \(-4x\left(x-7\right)+4x\left(x^2-5\right)=28x^2-13\)
\(\Leftrightarrow-4x^2+28x+4x^3-20x=28x^2-13\)
\(\Leftrightarrow-32x^2+8x+4x^3+13=0\)( vô nghiệm )
tìm x:
a) \(\left(2x+5\right)\left(4x-10\right)+4x.\left(3-2x\right)^2=0\)
b) \(\left(2x-3\right)^2-\left(3x+1\right)^2=0\)
a: =>8x^2-20x+20x-50+4x(4x^2-12x+9)=0
=>8x^2-50+8x^3-48x^2+36x=0
=>8x^3-40x^2+36x-50=0
=>\(x\simeq4,29\)
b: =>(2x-3-3x-1)(2x-3+3x+1)=0
=>(-x-4)(5x-2)=0
=>x=2/5 hoặc x=-4
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25 tháng 2 2023 lúc 14:40
Tính:
\(a)\left(-2x^2\right)\cdot\left(3x-4x^3+7-x^2\right)\)
\(b)\left(x+3\right)\cdot\left(2x^2-3x-5\right)\)
\(c)\left(-6x^5+7x^4-6x^3\right):3x^3\)
\(d)\left(9x^2-4\right):\left(3x+2\right)\)
\(e)\left(2x^4-13x^3+15x^2+11x-3\right):\left(x^2-4x-3\right)\)
a: \(=-2x^2\cdot3x+2x^2\cdot4X^3-2x^2\cdot7+2x^2\cdot x^2\)
\(=8x^5+2x^4-6x^3-14x^2\)
b: \(=2x^3-3x^2-5x+6x^2-9x-15\)
\(=2x^3+3x^2-14x-15\)
c: \(=\dfrac{-6x^5}{3x^3}+\dfrac{7x^4}{3x^3}-\dfrac{6x^3}{3x^3}=-2x^2+\dfrac{7}{3}x-2\)
d: \(=\dfrac{\left(3x-2\right)\left(3x+2\right)}{3x+2}=3x-2\)
e: \(=\dfrac{2x^4-8x^3-6x^2-5x^3+20x^2+15x+x^2-4x-3}{x^2-4x-3}\)
=2x^2-5x+1
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giải pt :
a, \(\left(2x-6\right)\sqrt{x+4}-\left(x-5\right)\sqrt{2x+3}=3\left(x-1\right)\)
b, \(\left(4x+1\right)\sqrt{x+2}-\left(4x-1\right)\sqrt{x-2}=21\)
c, \(\left(4x+2\right)\sqrt{x+1}-\left(4x-2\right)\sqrt{x-1}=9\)
d, \(\left(2x-4\right)\sqrt{3x-2}+\sqrt{x+3}=5x-7+\sqrt{3x^2+7x-6}\)
Tìm x biết \(\left|4x^2+\left|3x+2\right|\right|=4x^2+2x+3\).Tập hợp giá trị x thõa mãn là()
