K
Khách

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

10 tháng 7 2019

1) \(\left(3x+7\right)^2-\left(2x-3\right)^2=0\)

\(\Leftrightarrow\left(3x+7-2x+3\right)\left(3x+7+2x-3\right)=0\)

\(\Leftrightarrow\left(x+10\right)\left(5x+4\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x+10=0\\5x+4=0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=-10\\x=\frac{-4}{5}\end{cases}}\)

Vạy ...

phần 2 tương tự áp dụng \(a^2-b^2=\left(a-b\right)\left(a+b\right)\)

10 tháng 7 2019

\((4x-1)^2-(5-3x)^2=0\)

\(\Leftrightarrow(4x-1-5-3x)(4x+1+5-3x)=0\)

\(\Leftrightarrow(x-6)(x+6)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-6=0\\x+6=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=6\\x=-6\end{cases}}\)

Vậy : ...

12 tháng 7 2021

undefined

a) Ta có: \(a^3y^3+125\)

\(=\left(ay+5\right)\left(a^2y^2-5ay+25\right)\)

b) Ta có: \(8x^3-y^3-6xy\cdot\left(2x-y\right)\)

\(=\left(2x-y\right)\left(4x^2+2xy+y^2\right)-6xy\left(2x-y\right)\)

\(=\left(2x-y\right)\left(4x^2+2xy-6xy+y^2\right)\)

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

a: =4x^2+8x-3x-6

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

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

b: =3(3x^2-2x-1)

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

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

c: =2x^2-4x+x-2

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

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

d: =3x^2+3x-2x-2

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

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

e: =3x^2+9x+x+3

=3x(x+3)+(x+3)

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

24 tháng 8 2023

a) \(4x^2+5x-6\)

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

\(=\left(4x^2+8x\right)-\left(3x+6\right)\)

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

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

b) \(9x^2-6x-3\)

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

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

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

\(=3\left(x-1\right)\left(3x+1\right)\)

c) \(2x^2-3x-2\)

\(=2x^2-4x+x-2\)

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

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

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

d) \(3x^2+x-2\)

\(=3x^2+3x-2x-2\)

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

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

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

e) \(3x^2+10x+3\)

\(=3x^2+9x+x+3\)

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

\(=\left(x+3\right)\left(3x+1\right)\)

a) \(\left(2x+5\right)^2\)\(-\left(x-9\right)^2\)

=\(\left(2x+5+x-9\right).\left(2x+5-x+9\right)\)

=\(\left(3x-4\right).\left(x+14\right)\)

10 tháng 7 2019

1/ \(\left(9x^2-25\right)-\left(6x-10\right)=0\)

\(\Leftrightarrow9x^2-6x-35=0\)

\(\Leftrightarrow\left(2x-1\right)^2-36=0\)

\(\Leftrightarrow\left(2x-7\right)\left(2x+6\right)=0\)

2/ \(\left(3x+5\right)^2-4x^2=0\)

\(\Leftrightarrow\left(x+5\right)\left(5x+5\right)=0\)

3/ \(25x^2-\left(4x-3\right)^2=0\)

\(\Leftrightarrow\left(x+3\right)\left(9x-3\right)=0\)

10 tháng 7 2019

1) ( 9x2 - 25 ) - ( 6x - 10 ) = 0

\(\Leftrightarrow\) [ ( 3x)2 - 52 ] - 2.( 3x + 5 ) = 0

\(\Leftrightarrow\)( 3x - 5 ).( 3x + 5 ) - 2.( 3x - 5 ) = 0

\(\Leftrightarrow\) ( 3x + 5 ).( 3x + 5 - 2 ) = 0

\(\Leftrightarrow\)( 3x + 5 ).( 3x + 3 ) = 0

\(\Leftrightarrow\)\(\orbr{\begin{cases}3x+5=0\\3x+3=0\end{cases}}\)\(\Leftrightarrow\)\(\orbr{\begin{cases}3x=-5\\3x=-3\end{cases}}\)\(\Leftrightarrow\)\(\orbr{\begin{cases}x=\frac{-5}{3}\\x=-1\end{cases}}\)

Vậy x = \(\frac{-5}{3}\) , x = -1

2) ( 3x + 5 )2 - 4x2  = 0

\(\Leftrightarrow\) ( 3x + 5 - 2x ).( 3x + 5 + 2x ) = 0

\(\Leftrightarrow\)( x + 5 ).( 5x + 5 ) = 0

\(\Leftrightarrow\)\(\orbr{\begin{cases}x+5=0\\5x+5=0\end{cases}}\)\(\Leftrightarrow\)\(\orbr{\begin{cases}x=-5\\x=-1\end{cases}}\)

Vậy x = -5 , x = -1

3) 25x2 - ( 4x - 3 )2 = 0

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

\(\Leftrightarrow\) ( 5x - 4x + 3 ).(5x + 4x - 3 ) = 0

\(\Leftrightarrow\)( x + 3 ).( 9x - 3 ) = 0

\(\Leftrightarrow\)\(\orbr{\begin{cases}x+3=0\\9x-3=0\end{cases}}\)\(\Leftrightarrow\)\(\orbr{\begin{cases}x=-3\\9x=3\end{cases}}\)\(\Leftrightarrow\)\(\orbr{\begin{cases}x=-3\\x=\frac{1}{3}\end{cases}}\)

Vậy x = 3 , x = \(\frac{1}{3}\)

10 tháng 10 2021

a) \(=\left(x-2\right)^2\)

b) \(=\left(2x+1\right)^2\)

c) \(=\left(4x-3y\right)\left(4x+3y\right)\)

d) \(=\left(4-x-3\right)\left(4+x+3\right)=\left(1-x\right)\left(x+7\right)\)

e) \(=\left(2x-3x+1\right)\left(2x+3x-1\right)=\left(1-x\right)\left(5x-1\right)\)

f) \(=\left(x-y\right)\left(x^2+xy+y^2\right)\)

g) \(=\left(x+3\right)\left(x^2-3x+9\right)\)

h) \(=\left(x+2\right)^3\)

i) \(=\left(1-x\right)^3\)

10 tháng 10 2021

a/ $=(x-2)^2$

b/ $=(2x+1)^2$

c/ $=(4x-3y)(4x+3y)$

d/ $=(1-x)(x+7)$

e/ $=(-x+1)(5x-1)$

f/ $=(x-y)(x^2+xy+y^2)$

g/ $=(3+x)(9-3x+x^2)$

h/ $=(x+2)^3$

i/ $=(1-x)^3$

10 tháng 10 2021

a: \(x^2-4x+4=\left(x-2\right)^2\)

b: \(4x^2+4x+1=\left(2x+1\right)^2\)

g: \(x^3+27=\left(x+3\right)\left(x^2-3x+9\right)\)

a: \(x^3-2x+4\)

\(=x^3+2x^2-2x^2-4x+2x+4\)

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

b: \(x^3-4x^2+12x-27\)

\(=\left(x-3\right)\left(x^2+3x+9\right)-4x\left(x-3\right)\)

\(=\left(x-3\right)\left(x^2-x+9\right)\)

c: \(x^3+2x^2+2x+1\)

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

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

5 tháng 8 2021

giups mình với nha

 

5 tháng 7 2016

a) \(x^2+4x+3=\left(x^2+4x+4\right)-1=\left(x+2\right)^2-1^2=\left(x+1\right)\left(x+3\right)\) (mình sửa lại)

b) \(x^2+8x-9=\left(x^2+8x+16\right)-25=\left(x+4\right)^2-5^2=\left(x-1\right)\left(x+9\right)\)

c) \(3x^2+6x-9=3\left[\left(x^2+2x+1\right)-4\right]=3\left[\left(x+1\right)^2-2^2\right]=3\left(x-1\right)\left(x+3\right)\)

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

 

6 tháng 7 2016

tik nhé Toán lớp 8