Câu hỏi của Trung Art

Question

Bài 3: Tìm x biết :

a) x(8x - 2) - 8x2 + 12 = 0;

b) x( 4x - 5) - (2x + 1) 2 = 0;

B.Thị Anh Thơ · Accepted Answer

a,$x\left(8x-2\right)-8x^2+12=0$

$\Leftrightarrow8x^2-2x-8x^2+12=0$

$\Leftrightarrow-2x+12=0$

$\Leftrightarrow-2x=-12$

$\Leftrightarrow x=6$

b,$x\left(4x-4\right)-\left(2x+1\right)^2=0$

$\Leftrightarrow4x^2-5x-\left(4x^2+4x+1\right)=0$

$\Leftrightarrow4x^2-5x-4x^2-4x-1=0$

$\Leftrightarrow-9x-1=0$

$\Leftrightarrow-9x=1$

$\Leftrightarrow x=\frac{-1}{9}$Câu trả lời: a,$x\left(8x-2\right)-8x^2+12=0$

$\Leftrightarrow8x^2-2x-8x^2+12=0$

$\Leftrightarrow-2x+12=0$

$\Leftrightarrow-2x=-12$

$\Leftrightarrow x=6$

b,$x\left(4x-4\right)-\left(2x+1\right)^2=0$

$\Leftrightarrow4x^2-5x-\left(4x^2+4x+1\right)=0$

$\Leftrightarrow4x^2-5x-4x^2-4x-1=0$

$\Leftrightarrow-9x-1=0$

$\Leftrightarrow-9x=1$

$\Leftrightarrow x=\frac{-1}{9}$

Buddy · Answer

A:x(8x -2) -8x2+12=0

8x2-2x-8x2+12=0

-2x+12=0

-2x=-12

x=6

Vậy......

b:x(4x-5)-(2x+1)2=0

4x2-5x-4x2-4x-1=0

-9x=1

x=-1/9

Vậy....Câu trả lời: A:x(8x -2) -8x2+12=0