Question

1) 4x² - 2x + 3 - 4x(x - 5) = 7x - 3

2) -3x(x - 5) + 5(x - 1) + 3x² = 4 - x 

Tìm X 

 

Answer 1

1) 4x² - 2x + 3 - 4x(x - 5) = 7x - 3

<=> 4x² - 9x - 4x² + 20x = -6

<=> 11x = -6

<=> x = -6/11

2. -3x(x - 5) + 5(x - 1) + 3x² = 4 - x

<=> -3x² + 15x + 5x - 5 + 3x² + x = 4

<=> 21x = 9

<=> x = 3/7

Answer 2

1.\(4x^2-2x+3-4x\left(x-5\right)=7x-3\)

\(\Leftrightarrow4x^2-2x+3-4x^2+20x=7x-3\)

\(\Leftrightarrow4x^2-2x+3-4x^2+20x-7x+3=0\)

\(\Leftrightarrow11x+6=0\)

\(\Leftrightarrow11x=-6\)

\(\Leftrightarrow x=-\frac{6}{11}\)

Vậy .....

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

\(\Leftrightarrow-3x^2+15x+5x-5+3x^2-4+x=0\)

\(\Leftrightarrow21x-9=0\)

\(\Leftrightarrow x=\frac{3}{7}\)

Answer 3

a, \(4x^2-2x+3-4x\left(x-5\right)=7x-3\)

\(\Leftrightarrow4x^2-2x+3-4x^2+20x=7x-3\)

\(\Leftrightarrow18x+3=7x-3\Leftrightarrow11x=-6\Leftrightarrow x=-\frac{6}{11}\)

b, \(-3x\left(x-5\right)+5\left(x-1\right)+3x^2=4-x\)

\(\Leftrightarrow-3x^2+15x+5x-5+3x^2=4-x\)

\(\Leftrightarrow20x-5=4-x\Leftrightarrow21x=9\Leftrightarrow x=\frac{9}{21}=\frac{3}{7}\)

Answer 4

Trả lời:

1) 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

Vậy x = - 6/11 là nghiệm của pt

2) - 3x ( x - 5 ) + 5 ( x - 1 ) + 3x² = 4 - x

<=> - 3x² + 15x + 5x - 5 + 3x² = 4 - x

<=> 20x - 5 = 4 - x

<=> 20x + x = 4 + 5

<=> 21x = 9

<=> x = 3/7

Vậy x = 3/7 là nghiệm của pt