Question

Tìm x

a/ 8x^2-(2x+5)(4x-2)-9=0

PTĐTTNT

1/ 5x^2-10-x+2

2/ 3x^2-6xy-3y^2-12z^2

3/ x^2-3x+2

Answer 1

Tìm x:

\(8x^2-\left(2x+5\right)\left(4x-2\right)-9=0\)

\(\Leftrightarrow8x^2-\left(8x^2-4x+20x-10\right)-9=0\)

​\(\Leftrightarrow8x^2-8x^2+4x-20x+10-9=0\)​

\(\Leftrightarrow-16x+1=0\)

\(\Leftrightarrow-16x=-1\)

\(\Leftrightarrow x=\dfrac{-1}{-16}=\dfrac{1}{16}\)

Vậy \(x=\dfrac{1}{16}\)

Answer 2

Bài 1:

\(a,8x^2-\left(2x+5\right)\left(4x-2\right)-9=0\)

\(\Rightarrow8x^2-\left(8x^2+16x-10\right)-9=0\)

\(\Rightarrow8x^2-8x^2-16x+10-9=0\)

\(\Rightarrow-16x+1=0\)

\(\Rightarrow x=\dfrac{1}{16}\)

Answer 3

Tìm x:

a) 8x² - (2x + 5)(4x - 2) - 9 =0

8x² - (8x² - 4x + 20x - 10) - 9= 0

8x² - (8x² + 16x - 10) - 9 =0

8x² - 8x² - 16x + 10 - 9 = 0

- 16x + 1 =0

- 16x = - 1

x = \(\frac{1}{16}\)

Vậy \(x = \frac{1}{16}\)

PTĐTTNT:

3/ x² - 3x + 2

= x² - x - 2x + 2

= x(x - 1) - 2(x - 1)

= (x - 1)(x - 2)

pn coi lại câu 1 và 2 nhé

Answer 4

C₁ :

\(a,8x^2-\left(2x+5\right)\left(4x-2\right)-9=0\)

\(\Rightarrow8x^2-\left(8x^2+16x-10\right)-9=0\)

\(\Rightarrow8x^2-8x^2-16x+10-9=0\)

\(\Rightarrow-16x+1=0\)

\(\Rightarrow x=\dfrac{1}{16}\)

Answer 5

1/ 5x²-10x-x+2

=5x(x-2)-(x-2)

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

Answer 6

2/ 3x²-6xy+3y²-12z²

=3(x²-2xy+y²-4z² )

3{(x-y)²-4z² }

3(x-y-2z)(x-y+2z)

Answer 7

x²-3x+2

=x²-2x-x+2

=x(x-2)-(x-2)

=(x-1)(x-2)

Answer 8

Tìm x:

8x² - (2x + 5)(4x - 2) - 9 = 0

8x² - (8x² - 4x + 20x - 10) - 9 = 0

8x² - 8x² +4x - 20x + 10 - 9 = 0

-16x + 1 = 0

=> -16x = -1

=> x = \(\dfrac{1}{16}\)

Phân tích Đa thức thành nhân tử:

con a bn xem lại đi nhé

mạn phép chữa đề:

b) 3x² - 6xy + 3y² - 12z²

= 3(x² - 2xy + y² - 4z²)

= 3[(x² - 2xy + y²) - 4z²]

= 3[(x - y)² - 4z²]

= 3(x - y + z)(x - y - z)

c) x² - 3x + 2

C1:

x² - 3x + 2

= x² - 3x - 1 + 3

= (x² - 1) - (3x - 3)

= (x - 1)(x + 1) - 3(x - 1)

= (x - 1)(x + 1 - 3)

=(x - 1)(x - 2)

C2: x² - 3x + 2

= 3x² - 2x² - 3x + 2

= (3x² - 3x) - (2x² - 2)

= 3x(x - 1) - 2(x² - 1)

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

= (x - 1)[3x - 2(x + 1)]

= (x - 1)(3x - 2x - 2)

= (x - 1)(x - 2)

C3: x² - 3x + 2

= x² - x - 2x + 2

= (x² - x) - (2x - 2)

= x(x - 1) - 2(x - 1)

= (x - 2)(x - 1)

Chúc Bn Hok Tốt

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Answer 9

1/ 5x² - 10 - x² + 2 ( sửa đề )

= 5( x² - 2) - (x² - 2)

= 4(x² - 2)

2/ 3x² - 6xy + 3y² - 12z² ( sửa đề)

= 3(x² - 2xy + y² - 4z²)

= 3[ ( x - y)² - ( 2z)²]

= 3( x - y - 2z)( x - y + 2z)

3/ x² - 3x + 2

= x² - x - 2x + 2

= x( x - 1) - 2(x - 1)

= ( x - 1)( x - 2)