1.

<=> \(\left[{}\begin{matrix}4-3x=0\\10-5x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{4}{3}\\x=2\end{matrix}\right.\)

2.

<=>\(\left[{}\begin{matrix}7-2x=0\\4+8x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=-\dfrac{1}{2}\end{matrix}\right.\)

3.

<=>\(\left[{}\begin{matrix}9-7x=0\\11-3x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{7}\\x=\dfrac{11}{3}\end{matrix}\right.\)

4.

<=>\(\left[{}\begin{matrix}7-14x=0\\x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=2\end{matrix}\right.\)

5. 

<=>\(\left[{}\begin{matrix}\dfrac{7}{8}-2x=0\\3x+\dfrac{1}{3}=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{16}\\x=-\dfrac{1}{9}\end{matrix}\right.\)

6,7. ko đủ điều kiện tìm

a) 8( 3x - 2 ) - 14x = 2( 4 – 7x ) + 15x

⇔ 24x – 16 -14x = 8 – 14x + 15x

⇔ 10x -16 = 8 + x

⇔ 9x = 24

⇔ x = 24/9

b) ( 3x – 1 )( x – 3 ) – 9 + x2 = 0

⇔ (3x -1)( x – 3) + (x - 3)( x + 3) = 0

⇔ (x - 3)(3x - 1 + x - 3) = 0

⇔ (x - 3)(4x - 4) = 0

c) |x - 2| = 2x - 3

TH1: x - 2 ≥ 0 ⇔ x ≥ 2

Khi đó: x - 2 = 2x – 3

⇔ 2x – x = -2 + 3

⇔ x = 1 (không TM điều kiện x ≥ 2)

TH2: x – 2 < 0 ⇔ x < 2

Khi đó: x-2 = -(2x – 3)

⇔ x – 2 = -2x + 3

⇔ 3x = 5

⇔ x = 5/3 ( TM điều kiện x < 2)

MTC: x(x-2)

ĐKXĐ: x ≠ 0;x ≠ 2

Đối chiếu với ĐKXĐ thì pt có nghiệm x = - 1

a) Trường hợp 1. Xét 4 - 5x = 5 - 6x.

Tìm được x = 1.

phần cuối mk chụp ko đc hết . chỗ cuối là bằng \(\frac{-5}{-3}\)=\(\frac{5}{3}\)

Bài 1.

a)

\((x-2)(2x-1)-(2x-3)(x-1)-2\\=2x^2-x-4x+2-(2x^2-2x-3x+3)-2\\=2x^2-5x+2-(2x^2-5x+3)-2\\=2x^2-5x+2-2x^2+5x-3-2\\=(2x^2-2x^2)+(-5x+5x)+(2-3-2)\\=-3\)

b)

\(x(x+3y+1)-2y(x-1)-(y+x+1)x\\=x^2+3xy+x-2xy+2y-xy-x^2-x\\=(x^2-x^2)+(3xy-2xy-xy)+(x-x)+2y\\=2y\)

Bài 2.

a)

\((14x^3+12x^2-14x):2x=(x+2)(3x-4)\\\Leftrightarrow 14x^3:2x+12x^2:2x-14x:2x=3x^2-4x+6x-8\\ \Leftrightarrow 7x^2+6x-7=3x^2+2x-8\\\Leftrightarrow (7x^2-3x^2)+(6x-2x)+(-7+8)=0\\\Leftrightarrow 4x^2+4x+1=0\\\Leftrightarrow (2x)^2+2\cdot 2x\cdot 1+1^2=0\\\Leftrightarrow (2x+1)^2=0\\\Leftrightarrow 2x+1=0\\\Leftrightarrow 2x=-1\\\Leftrightarrow x=\frac{-1}2\)

b)

\((4x-5)(6x+1)-(8x+3)(3x-4)=15\\\Leftrightarrow 24x^2+4x-30x-5-(24x^2-32x+9x-12)=15\\\Leftrightarrow 24x^2-26x-5-(24x^2-23x-12)=15\\\Leftrightarrow 24x^2-26x-5-24x^2+23x+12=15\\\Leftrightarrow -3x+7=15\\\Leftrightarrow -3x=8\\\Leftrightarrow x=\frac{-8}3\\Toru\)

a) 4x²  - 2x + 3 - 4x.(x - 5) = 7x - 3

--> 4x² - 2x + 3 - 4x² + 20x = 7x - 3

--> 4x² - 2x - 4x² + 20x - 7x = -3 - 3

--> 11x = -6

--> x = \(\frac{-6}{11}\)

b) -3x.(x - 5) + 5.(x - 1) + 3x² = 4x

--> -3x² + 15x + 5x - 5 + 3x² = 4x

--> -3x²  + 15x + 5x + 3x² - 4x = 5 

--> 16x = 5

--> x = \(\frac{5}{16}\)

c) 7x.(x - 2) - 5.(x - 1) = 21x² - 14x² + 3

--> 7x² - 14x - 5x + 5 = 7x² + 3 

--> 7x²  - 14x - 5x - 7x²  = -5 + 3 

--> -19x = -2 

--> x = \(\frac{2}{19}\)

d) 3.(5x - 1) - x.(x - 2) + x² - 13x = 7

--> 15x - 3 - x² + 2x + x² - 13x = 7

--> 15x - x² + 2x + x² - 13x = 3 + 7

--> 4x = 10

--> x = \(\frac{5}{2}\)

e) \(\frac{1}{5}\)x.(10x - 15) - 2x.(x - 5) = 12

--> 2x² - 3x - 2x² + 10x = 12

--> 7x = 12

--> x = \(\frac{12}{7}\)

~ Học tốt ~

a) 4x² - 2x + 3 - 4x(x - 5) = 7x - 3

=> 4x² - 2x + 3 - 4x² + 20x = 7x - 3

=> 18x + 3 = 7x - 3

=> 18x - 7x = -3 - 3

=> 11x = -6

=>  x = -6/11

b) -3x(x - 5) + 5(x - 1) + 3x² = 4x

=> -3x² + 15x + 5x - 5 + 3x² = 4x

=> 20x - 5 = 4x

=> 20x - 4x = 5

=> 16x = 5

=> x = 5/16

\(c,7x\left(x-2\right)-5\left(x-1\right)=21x^2-14x^2+3\)

\(\Leftrightarrow7x^2-14x-5x+5=7x^2+3\)

\(\Leftrightarrow7x^2-7x^2-19x=3-5\)

\(\Leftrightarrow-19x=-2\)

\(\Leftrightarrow x=\frac{2}{19}\)

a) 4x² - 2x + 3 - 4x.(x - 5) = 7x - 3

<=> 18x + 3 = 7x - 3

<=> 18x = 7x - 3 - 3

<=> 18x = 7x - 6

<=> 18x - 7x = -6

<=> 11x = -6

<=> x = -6/11

=> x = -6/11

b) -3x.(x - 5) + 5.(x - 1) + 3x² = 4x

<=> 20x - 5 = 4x

<=> 20x = 4x + 5

<=> 20x - 4x = 5

<=> 16x = 5

<=> x = 5/16

=> x = 5/16

c) 7x.(x - 2) - 5.(x - 1) = 21x² - 14x² + 3

<=> 7x.(x - 2) - 5.(x - 1) = 7x² + 3

<=> 7x² - 19x + 5 = 7x² + 3

<=> 7x² - 19x = 7x² + 3 - 5

<=> 7x² - 19x = 7x² - 2 

<=> 7x² - 19x - 7x² = -2

<=> -19x = -2

<=> x = 2/19

=> x = 2/19

d) 3.(5x - 1) - x.(x - 2) + x² - 13x = 7

<=> 4x - 3 = 7

<=> 4x = 7 + 3

<=> 4x = 10

<=> x = 10/4

=> x = 5/2

e) 1/5x.(10x - 15) - 2x.(x - 5) = 12

<=> x(2x - 3) - 2x(x - 5) = 12

<=> 7x = 12

<=> x = 12/7

=> x = 12/7