K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

19 tháng 9 2016

những bài này dễ lắm bn à, chỉ đơn thuần là áp dụng hđt thui

a)  (x+1)(4x-8) =0

x+1=0

x= -1

4x-8 =0

x = 2

b) =  2(x+1)(x+1) = 2(x+1)2

..........................

6 tháng 12 2017

a) \(=\left(x-2y\right)\left(x^2+5x\right)\)

b) \(=\left(x-1\right)\left(x^2+2x+1\right)=\left(x-1\right)\left(x+1\right)^2\)

c) \(=\left(x^2+1-2x\right)\left(x^2+1+2x\right)\)

    \(=\left(x^2-2x+1\right)\left(x^2+2x+1\right)\)

    \(=\left(x-1\right)^2\left(x+1\right)^2\)

d) \(=3\left(x+3\right)-\left(x-3\right)\left(x+3\right)\)

     \(=\left(x+3\right)\left(3-x+3\right)\)

     \(=\left(x+3\right)\left(6-x\right)\)

e) \(=\left(x^2-\frac{1}{3}x\right)\left(x^2+\frac{1}{3}x\right)\)

f) \(=2x\left(x-y\right)-16\left(x-y\right)\)

    \(=2\left(x-y\right)\left(x-8\right)\)

  

9 tháng 12 2018

a) \(2x\left(x-3\right)^2+5x\left(3-x\right)\)

\(=2x\left(x-3\right)^2-5x\left(x-3\right)\)

\(=\left(x-3\right)\left[2x\left(x-3\right)-5x\right]\)

\(=\left(x-3\right)\left(2x^2-6x-5x\right)\)

\(=\left(x-3\right)\left(2x^2-11x\right)\)

\(=x\left(x-3\right)\left(2x-11\right)\)

b) \(\left(x+3\right)^2-4\left(y^2-2y+1\right)\)

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

\(=\left(x+3\right)^2-\left[2\left(y-1\right)\right]^2\)

\(=\left[\left(x+3\right)-2\left(y-1\right)\right]\left[\left(x+3\right)+2\left(y-1\right)\right]\)

\(=\left(x+3-2y+2\right)\left(x+3+2y-2\right)\)

\(=\left(x-2y+5\right)\left(x+2y+1\right)\)

9 tháng 12 2018

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

\(=\left(x-3\right).\left(2x^2-11x\right)=\left(x-3\right).x.\left(2x-11\right)\)

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

 \(=\left(x+3\right)^2-\left[2.\left(y-1\right)\right]^2=\left(x-2y+1\right).\left(x+2y+5\right)\)

2 tháng 10 2018

1.

a)  khong bit bạn xem đề sai k

b) x2 -4x +4 - (x+3)(x-3) = 0

<=> x2 -4x + 4 - x2 +9 = 0

<=> -4x = -13 <=> x= 13/4

c) x2 -3x +2 = 0

<=> x2 -x -2x +2 = 0

<=> x(x-1) - 2( x-1) = 0

<=> (x-1)(x-2) = 0 <=> x = 1 hoặc 2

2.

a) x-8 = (x2 -4)(x2 +4) = (x-2)(x+2)(x2 +4)

b)x2 -y2 -2x+2y = (x-y)(x+y) - 2(x-y) = (x-y)(x+y-2)

c)x2 - 5x +6 = x2 -3x -2x +6 = x(x-3) - 2(x-3) = (x-2)(x-3)

2 tháng 10 2018

a) \(\left(3x-1\right)^2+ \left(x+3\right)^2-5\left(2x-3\right)\left(x+3\right)=0\)

\(\Leftrightarrow-15x+55=0\)

\(\Leftrightarrow-15x=0-55\)

\(\Leftrightarrow-15x=-55\)

\(\Leftrightarrow x=\frac{-55}{-15}\)

\(\Rightarrow x=\frac{11}{3}\)

b) \(x^2-4x+4-\left(x+3\right)\left(x-3\right)=0\)

\(\Leftrightarrow x^2-4x-\left(x+3\right)\left(x-3\right)=4-0\)

\(\Leftrightarrow x^2-4x-\left(x+3\right)\left(x-3\right)=4\)

\(\Leftrightarrow4x+9=4\)

\(\Leftrightarrow4x=4+9\)

\(\Leftrightarrow4x=13\)

\(\Rightarrow x=\frac{13}{4}\)

b. x4 - x2 - 2x - 1

=x4-(x2+2x+1)

=x4-(x+1)2

=(x2-x-1)(x2+x+1)

d. ( x2 + 3x + 1 ) ( x2 + 3x - 3 ) - 5

Đặt x2+3x=y

=> (y+1)(y-3)-5=y2-2y-8=(y-1)2-9

=(y-4)(y+2)

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