a) 2x² - 3x - 2 = 0.

<=> (2x + 1)(x - 2) = 0

<=> 2x + 1 = 0 hoặc x - 2 = 0

<=> x = -1/2 hoặc x = 2

b) 3x² - 7x - 10 = 0.

<=> (x + 1)(3x - 10) = 0

<=> x = -1 hoặc x = 10/3

c) 2x² - 5x + 3 = 0.

<=> (x - 1)(2x - 3) = 0

<=> x = 1 hoặc x = 3/2

bạn tách từng bài ra bn

tl câu hỏi trên cho mik ik

giải phương trình làm dell gì, lớp 8 mà

a) \(2x^2-5x^2+6x+13=0\)

\(\Leftrightarrow-3x^2+6x+13=0\)

\(\Leftrightarrow3x^2-6x-13=0\left(1\right)\)

\(\Delta'=9+39=48>0\Rightarrow\sqrt[]{\Delta'}=4\sqrt[]{3}\)

Pt (1) có 2 nghiệm phân biệt là :

\(\left[{}\begin{matrix}x=\dfrac{3+4\sqrt[]{3}}{3}=1+\dfrac{4\sqrt[]{3}}{3}\\x=\dfrac{3-4\sqrt[]{3}}{3}=1-\dfrac{4\sqrt[]{3}}{3}\end{matrix}\right.\)

b) \(x^2-5x=-4\)

\(\Leftrightarrow x^2-5x+4=0\)

\(\Leftrightarrow x^2-x-4x+4=0\)

\(\Leftrightarrow x\left(x-1\right)-4\left(x-1\right)=0\)

\(\Leftrightarrow\left(x-1\right)\left(x-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x-4=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=4\end{matrix}\right.\)

Chọn A

a: \(\Leftrightarrow\left(-x+3\right)\left(x+6\right)=18\)

\(\Leftrightarrow-x^2-6x+3x+18-18=0\)

\(\Leftrightarrow-x\left(x+3\right)=0\)

=>x=0 hoặc x=-3

b: \(\Leftrightarrow x\left(3x^2+6x-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\3x^2+6x-4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x^2+2x-\dfrac{4}{3}=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\\left(x+1\right)^2=\dfrac{7}{3}\end{matrix}\right.\Leftrightarrow x\in\left\{0;\dfrac{\sqrt{21}}{3}-1;\dfrac{-\sqrt{21}}{3}-1\right\}\)

c: =>x(3x-5)=0

=>x=0 hoặc x=5/3

d: =>(x-2)(x+2)=0

=>x=2 hoặc x=-2

1.

a) \(2x^4-4x^3+2x^2\)

\(=2x^2\left(x^2-2x+1\right)\)

\(=2x^2\left(x-1\right)^2\)

b) \(2x^2-2xy+5x-5y\)

\(=\left(2x^2-2xy\right)+\left(5x-5y\right)\)

\(=2x\left(x-y\right)+5\left(x-y\right)\)

\(=\left(x-y\right)\cdot\left(2x+5\right)\)

2 . 

a,

\(4x\left(x-3\right)-x+3=0\)

⇒\(4x\left(x-3\right)-\left(x-3\right)=0\)

⇒\(\left(x-3\right)\left(4x-1\right)=0\)

⇒\(\left[{}\begin{matrix}x-3=0\\4x-1=0\end{matrix}\right.\)

⇔\(\left[{}\begin{matrix}x=3\\4x=1\end{matrix}\right.\)

⇔\(\left[{}\begin{matrix}x=3\\x=\dfrac{1}{4}\end{matrix}\right.\)

vậy \(x\in\left\{3;\dfrac{1}{4}\right\}\)

b, 

\(\)\(\left(2x-3\right)^2-\left(x+1\right)^2=0\)

⇒\(\left(2x-3-x-1\right)\left(2x-3+x+1\right)\) = 0

⇒\(\left(x-4\right)\left(3x-2\right)=0\)

⇔\(\left[{}\begin{matrix}x-4=0\\3x-2=0\end{matrix}\right.\)

⇔\(\left[{}\begin{matrix}x=4\\3x=2\end{matrix}\right.\)

⇔\(\left[{}\begin{matrix}x=4\\x=\dfrac{2}{3}\end{matrix}\right.\)

vậy \(x\in\left\{4;\dfrac{2}{3}\right\}\)

ban tích cho mk vs nha

kh hiểu bn ơi

`4x=2+xx+1x<=>4x=2+3x<=>4x-3x=2<=>1x=2<=>x=2`

\(a,\) 

\(2x^2-5x-7=0\)

\(\Leftrightarrow2x^2+2x-7x+7\)

\(\Leftrightarrow2x\left(x+1\right)-7\left(x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+1=0\\2x-7=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=\dfrac{7}{2}\end{matrix}\right.\)

\(\left(2x+2\right)\left(x+\dfrac{7}{2}\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2x+2=0\\x+\dfrac{7}{2}=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-\dfrac{7}{2}\end{matrix}\right.\)

Vậy 2 pt ko tương đương

\(b,\left(2x-3\right)\left(x^2-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-3=0\\x^2-4=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\pm2\end{matrix}\right.\)

\(6x^2=24\Leftrightarrow x^2=4\Leftrightarrow x=\pm2\)

Vậy 2 pt tương đương

a: 2x^2-5x-7=0

=>2x^2-7x+2x-7=0

=>(2x-7)(x+1)=0

=>x=7/2 hoặc x=-1

(2x+2)(x+7/2)=0

=>(x+1)(x+7/2)=0

=>x=-7/2 hoặc x=-1

=>Hai phương trình ko tương đương

b: (2x-3)(x^2-4)=0

=>(2x-3)(x-2)(x+2)=0

=>\(x\in\left\{\dfrac{3}{2};2;-2\right\}\)

6x^2=24

=>x^2=4

=>x=2 hoặc x=-2

=>Hai phương trình ko tương đương

a) \(2x^2-5x+1=0\)

\(\Delta=b^2-4ac\Rightarrow\left(-5\right)^2-4.2.1=17>0\)

Phương trình có 2 nghiệm phân biệt:

\(x_1=\dfrac{-b+\sqrt{\Delta}}{2a}=\dfrac{-\left(-5\right)+\sqrt{17}}{2.2}=\dfrac{5+\sqrt{17}}{4}\)

\(x_2=\dfrac{-b-\sqrt{\Delta}}{2a}=\dfrac{-\left(-5\right)-\sqrt{17}}{2.2}=\dfrac{5-\sqrt{17}}{4}\)

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b) \(4x^2+4x+1=0\)

\(\Delta=b^2-4ac\Rightarrow4^2-4.4.1=0\)

Vậy phương trình có nghiệm kép:

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c) \(5x^2-x+2=0\)

\(\Delta=b^2-4a\Rightarrow\left(-1\right)^2-4.5.2=-39\)

Vậy phương trình vô nghiệm.

\(a,2x^2-5x+1=0\)

\(\Delta=-b^2-4ac\)

\(\Delta=25-8\)

\(\Delta=17\)

Vậy phương trình có `2` nghiệm phân biệt  :

\(x_1=\dfrac{-b+\sqrt{\Delta}}{2a}=\dfrac{5+\sqrt{17}}{4} \)

\(x_2=\dfrac{-b-\sqrt{\Delta}}{2a}=\dfrac{5-\sqrt{17}}{4}\)

\(b,4x^2+4x+1=0\)

\(\Delta=b^2-4ac\)

\(\Delta=16-16=0\)

Vậy phương trình có nghiệm kép :

\(x=\dfrac{-b}{2a}=-\dfrac{4}{8}=-\dfrac{1}{2}\)

\(c,5x^2-x+2=0\)

\(\Delta=1-40\)

\(\Delta=-39\)

Vậy phương trình vô nghiệm .