\(a,2x\left(12x-5\right)-8x\left(3x-1\right)=30\)

\(\Leftrightarrow24x^2-10x-24x^2+8x=30\)

\(\Leftrightarrow-2x=30\)

\(\Leftrightarrow x=-15\)

\(b,3x\left(3-2x\right)+6x\left(x-1\right)=15\)

\(\Leftrightarrow9x-6x^2+6x^2-6x=15\)

\(\Leftrightarrow3x=15\)

\(\Leftrightarrow x=-5\)

a) \(2x\left(12x-5\right)-8x\left(3x-1\right)=30\)

\(\Leftrightarrow24x^2-10x-24x^2+8x=30\)

\(\Leftrightarrow-10x+8x=30\Leftrightarrow-2x=30\Leftrightarrow x=\dfrac{30}{-2}=-15\)

vậy \(x=-15\)

b) đề có sai o bn

a) đề = 24x^2-10x-24x^2+8x=30

= -10x+8x =30

\(\Rightarrow\)x=-15

b)đề \(\Leftrightarrow\)9x-6x^2=6x^2-6x=15

\(\Leftrightarrow\)9x-6x^2-6x^2+6x=15

\(\Leftrightarrow\)15x=15

\(\Rightarrow\)x=1

a) \(2x\left(12x-5\right)-8x\left(3x-1\right)=30\)

\(24x^2-10x-24x^2+8x=30\)

\(-2x=30\)

\(x=-15\)

vay \(x=-15\)

b) \(3x\left(3-2x\right)+6x\left(x-1\right)=15\)

\(9x-6x^2+6x^2-6x=15\)

\(3x=15\)

\(x=5\)

a) x = -15

b) x= 5

* \(2x\left(12x-5\right)-8x\left(3x-1\right)=30\Leftrightarrow24x^2-10x-24x^2+8x=30\) \(\Leftrightarrow-10x+8x=30\Leftrightarrow-2x=30\Leftrightarrow x=\dfrac{30}{-2}=-15\) vậy \(x=-15\)

* \(3x\left(3-2x\right)+6x\left(x-1\right)=15\Leftrightarrow9x-6x^2+6x^2-6x=15\)

\(\Leftrightarrow9x-6x=15\Leftrightarrow3x=15\Leftrightarrow x=\dfrac{15}{3}=5\) vậy \(x=5\)

a, \(2x\left(12x-5\right)-8x\left(3x-1\right)=30\)

\(24x^2-10x-24x^2+8x=30\)

\(\left(24x^2-24x^2\right)-\left(10x-8x\right)=24\)

\(-2x=24\)

\(x=-12\)

b, \(3x\left(3-2x\right)+6x\left(x-1\right)=15\)

\(9x-6x^2+6x^2-6x=15\)

\(\left(9x-6x\right)+\left(-6x^2+6x^2\right)=15\)

\(3x=15\)

\(x=5\)

Câu a : \(2x\left(12x-5\right)-8x\left(3x-1\right)=30\)

\(\Leftrightarrow24x^2-10x-24x^2+8x=30\)

\(\Leftrightarrow-2x=30\)

\(\Leftrightarrow x=-15\)

Vậy \(x=-15\)

Câu b : \(3x\left(3-2x\right)+6x\left(x-1\right)=15\)

\(\Leftrightarrow9x-6x^2+6x^2-6x=15\)

\(\Leftrightarrow3x=15\)

\(\Leftrightarrow x=5\)

Vậy \(x=5\)

a, 2x(12x−5)−8x(3x−1)=302x(12x−5)−8x(3x−1)=30

24x2−10x−24x2+8x=3024x2−10x−24x2+8x=30

(24x2−24x2)−(10x−8x)=24(24x2−24x2)−(10x−8x)=24

−2x=24−2x=24

x=−12

b, 3x(3−2x)+6x(x−1)=153x(3−2x)+6x(x−1)=15

9x−6x2+6x2−6x=159x−6x2+6x2−6x=15

(9x−6x)+(−6x2+6x2)=15(9x−6x)+(−6x2+6x2)=15

3x=153x=15

x=5

a: ĐKXD: x<>0

\(\dfrac{14x^3+12x^2-14x}{2x}=\left(x+2\right)\left(3x-4\right)\)

=>\(\dfrac{2x\left(7x^2+6x-7\right)}{2x}=\left(x+2\right)\left(3x-4\right)\)

=>\(7x^2+6x-7=3x^2-4x+6x-8\)

=>\(7x^2+6x-7=3x^2+2x-8\)

=>\(4x^2+4x+1=0\)

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

=>2x+1=0

=>x=-1/2(nhận)

b: \(\left(4x-5\right)\left(6x+1\right)-\left(8x+3\right)\left(3x-4\right)=15\)

=>\(24x^2+4x-30x-5-\left(24x^2-32x+9x-12\right)=15\)

=>\(24x^2-26x-5-24x^2+23x+12=15\)

=>-3x+7=15

=>-3x=8

=>\(x=-\dfrac{8}{3}\)

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)

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

`@` `\text {Ans}`

`\downarrow`

`a)`

`3x(4x-1) - 2x(6x-3) = 30`

`=> 12x^2 - 3x - 12x^2 + 6x = 30`

`=> 3x = 30`

`=> x = 30 \div 3`

`=> x=10`

Vậy, `x=10`

`b)`

`2x(3-2x) + 2x(2x-1) = 15`

`=> 6x- 4x^2 + 4x^2 - 2x = 15`

`=> 4x = 15`

`=> x = 15/4`

Vậy, `x=15/4`

`c)`

`(5x-2)(4x-1) + (10x+3)(2x-1) = 1`

`=> 5x(4x-1) - 2(4x-1) + 10x(2x-1) + 3(2x-1)=1`

`=> 20x^2-5x - 8x + 2 + 20x^2 - 10x +6x - 3 =1`

`=> 40x^2 -17x - 1 = 1`

`d)`

`(x+2)(x+2)-(x-3)(x+1)=9`

`=> x^2 + 2x + 2x + 4 - x^2 - x + 3x + 3=9`

`=> 6x + 7 =9`

`=> 6x = 2`

`=> x=2/6 =1/3`

Vậy, `x=1/3`

`e)`

`(4x+1)(6x-3) = 7 + (3x-2)(8x+9)`

`=> 24x^2 - 12x + 6x - 3 = 7 + (3x-2)(8x+9)`

`=> 24x^2 - 12x + 6x - 3 = 7 + 24x^2 +11x - 18`

`=> 24x^2 - 6x - 3 = 24x^2 + 18x -11`

`=> 24x^2 - 6x - 3 - 24x^2 + 18x + 11 = 0`

`=> 12x +8 = 0`

`=> 12x = -8`

`=> x= -8/12 = -2/3`

Vậy, `x=-2/3`

`g)`

`(10x+2)(4x- 1)- (8x -3)(5x+2) =14`

`=> 40x^2 - 10x + 8x - 2 - 40x^2 - 16x + 15x + 6 = 14`

`=> -3x + 4 =14`

`=> -3x = 10`

`=> x= - 10/3`

Vậy, `x=-10/3`

Hello các bạn còn đó ko?

1) 4x-(2x-5)=21

4x-2x+5=21

2x+5=21

2x=21 -5

2x=16

x=16/2

x=8

2)14x+5=8x+10

14x-8x=10-5

6x=5

x=5/6

3) 15+5x=3x+30

5x-3x=30-15

2x=15

x=15/2

Vậy x=15/2