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1) \(4x^2+4x+1=\left(2x+1\right)^2\)
2)\(9x^2-24xy+16y^2=\left(3x-4y\right)^2\)
3)\(-x^2+10x-25=-\left(x-5\right)^2\)
4)\(1+12x+36x^2=\left(1+6x\right)^2\)
5) \(\dfrac{x^2}{4}+2xy+4y^2=\left(\dfrac{x}{2}+2y\right)^2\)
6) \(4x^2+4xy+y^2=\left(2x+y\right)^2\)
ĐKXĐ bạn tự tìm nha : )
k, Ta có : \(\frac{1-4x^2}{x^2+4x}:\frac{2-4x}{3x}=\frac{\left(1-2x\right)\left(1+2x\right)}{x\left(x+4\right)}.\frac{3x}{2\left(1-2x\right)}\)
\(=\frac{3x\left(1-2x\right)\left(1+2x\right)}{2x\left(x+4\right)\left(1-2x\right)}=\frac{3\left(1+2x\right)}{2\left(x+4\right)}\)
j, Ta có : \(\frac{x+y}{y-x}:\frac{x^2+xy}{3x^2-3y^2}=\frac{x+y}{y-x}:\frac{x\left(x+y\right)}{3\left(x^2-y^2\right)}=\frac{x+y}{y-x}.\frac{3\left(x-y\right)\left(x+y\right)}{x\left(x+y\right)}\)
\(=\frac{3\left(x-y\right)\left(x+y\right)}{x\left(y-x\right)}=\frac{3\left(x-y\right)\left(x+y\right)}{-x\left(x-y\right)}=\frac{-3\left(x+y\right)}{x}\)
i, Ta có : \(\frac{a^2+ab}{b-a}:\frac{a+b}{2a^2-2b^2}=\frac{a\left(a+b\right)}{-\left(a-b\right)}:\frac{a+b}{2\left(a^2-b^2\right)}=\frac{a\left(a+b\right)}{-\left(a-b\right)}.\frac{2\left(a-b\right)\left(a+b\right)}{a+b}\)
\(=\frac{2a\left(a+b\right)\left(a-b\right)}{-\left(a-b\right)}=-2a\left(a+b\right)\)
h, = k,
f, Ta có : \(\frac{x^2-36}{2x+10}.\frac{3}{6-x}=\frac{\left(x-6\right)\left(x+6\right)}{2\left(x+5\right)}.\frac{-3}{x-6}=\frac{-3\left(x-6\right)\left(x+6\right)}{2\left(x+5\right)\left(x-6\right)}=\frac{-3\left(x+6\right)}{2\left(x+5\right)}\)
Bài 1:
a: \(=\left(2x-1\right)^2-y^2=\left(2x-1-y\right)\left(2x-1+y\right)\)
b: \(=2x\left(x+y\right)-y\left(x+y\right)=\left(x+y\right)\left(2x-y\right)\)
Câu 2:
b: =>4x-1=2 hoặc 4x-1=-2
=>x=3/4 hoặc x=-1/4
c: =>(x-2018)(x-5)=0
=>x=5 hoặc x=2018
\(A=x^2-2x+4\)
\(A=\left(x^2-2x+1\right)+3\)
\(A=\left(x-1\right)^2+3\)
Vì \(\left(x-1\right)^2\ge0\) với mọi x
\(\Rightarrow\left(x-1\right)^2+3\ge3\) với mọi x
\(\Rightarrow Amin=3\Leftrightarrow x=1\)
a: \(=x^3-3x^2+3x-1-x^3-64+3x^2-3x\)
=-65
b \(=8x^3+27y^3-8x^3+27y^3-54y^3+27\)
=27
c: \(=y\left(x^4-y^4\right)-y\left(x^4-y^4\right)=0\)
d: \(=x^3-3x^2+3x-1-x^3+1-3x\left(1-x\right)\)
\(=-3x^2+3x-3x+3x^2=0\)
\(x^2-y^2+4-4x\)
\(=\left(x^2-4x+4\right)-y^2\)
\(=\left(x-2\right)^2-y^2\)
\(=\left(x-2+y\right)\left(x-2-y\right)\)
1)=x(x-1)-y(y-1)
2)=(x-2)2 -y2
3)=(2x+1)2 -9y2+1
#Mình k biết viết bình phương, thông cảm bạn nhé!
a) x4 - 4x2 + 4x - 1
= ( x2)2 - [ ( 2x)2 - 2.2x + 1]
= ( x2)2 - ( 2x - 1)2
= ( x2 - 2x +1)( x2 + 2x - 1)
= ( x -1)2( x2 + 2x - 1)
b) 4x2 - y2 + 4x + 1
= (2x)2 + 2.2x +1 - y2
= ( 2x +1)2 - y2
= ( 2x + 1 - y)( 2x + 1 + y)
\(\text{a) }x^4-4x^2+4x-1\\ \\=x^4-\left(4x^2-4x+1\right)\\ \\ =\left(x^2\right)^2-\left(2x-1\right)^2\\ \\=\left(x^2-2x+1\right)\left(x^2+2x-1\right)\\ \\=\left(x-1\right)^2\left(x^2+2x-1\right)\)
\(\text{b) }4x^2-y^2+4x+1\\ \\=\left(4x^2+4x+1\right)-y^2\\ \\=\left(2x+1\right)^2-y^2\\ \\=\left(2x+1+y\right)\left(2x+1-y\right)\)