a) t² - 8t + x² - 4x + 20 = ( t² - 8t + 16 ) + ( x² - 4x + 4 ) = ( t - 4 )² + ( x - 2 )²

b) 49t² + y² - 10y + 14t + 26 = ( 49t² + 14t + 1 ) + ( y² - 10y + 25 ) = ( 7t + 1 )² + ( y - 5 )²

c) 2x² + 4y² - 2x + 4xy + 1 = ( x² - 2x + 1 ) + ( x² + 4xy + 4y² ) = ( x - 1 )² + ( x + 2y )² ( thay 2 thành 1 vì 2 khó làm lắm:v )

Câu 1:

a, (x-1).(x²-x+1)

b, (2a+b).(2a-b)

Câu 2:

a,(2x-1).(x²-5x+3)

b,(-x²+4x-1).(-x+4)

c,(-2x-3).(x+4)+(-x+1)

d,(-3).(x+4).(x-7)+2.(x-5).(x+1)

Câu 3:

a,5x²-(2x+1).(x-2)-x.(3x+3)+7

b,(5x-2).(x+1)-(x-3).5x+1-17.(x-2)

Giup mình với 

Mình gửi kiểu kia ko được

1) x² + 10x + 26 + y² + 2y 

= (x² + 10x + 25) + (y² + 2y + 1)

= (x² + 5x + 5x + 25) + (y² + y + y + 1)

= x(x + 5) + 5(x + 5) + y(y +  1) + (y + 1)

= (x + 5)² + (y + 1)²

2) z² - 6z + 13 + t² + 4t 

= (z² - 6z + 9) + (t² + 4t + 4) 

= (z² - 3z - 3z + 9) + (t² + 2t + 2t + 4)

= z(z - 3) - 3(z - 3) + t(t + 2) + 2(t + 2)

= (z - 3)² + (t + 2)²

3) x² - 2xy + 2y² + 2y + 1

(x² - 2xy + y²) + (y² + 2y + 1)

= (x - xy - xy + y²) + (y² + y + y +1)

= x(x - y) - y(x - y) + y(y + 1) + (y + 1)

= (x - y)² + (y + 1)²

1)a)x²+10x+26+y²+2y

=(x²+10x+25)+(y²+2y+1)

=(x+5)²+(y+1)²

b)x²-2xy+2y²+2y+1

=(x²-2xy+y²)+(y²+2y+1)

=(x-y)²+(y+1)²

c)z²-6z+13+t²+4t

=(z²-6z+9)+(t²+4t+4)

=(z-3)²+(t+2)²

d)4x²+2z²-4xz-2z+1

=(4x²-4xz+z²)+(z²-2z+1)

=(2x-z)²+(z-1)²

2)a)(x-3)²-4=0

<=>(x-3-2)(x-3+2)=0

<=>(x-5)(x-1)=0

<=>x-5=0 hoặc x-1=0

<=>x=5 hoặc x=1

b)x²-2x=24

<=>x²-2x-24=0

<=>(x²-6x)+(4x-24)=0

<=>x(x-6)+4(x-6)=0

<=>(x-6)(x+4)=0

<=>x-6=0 hoặc x+4=0

<=>x=6 hoặc x=-4

a) x^2 + 10x + 26 + y^2 + 2y

=x²+10x+25+y²+2y+1

=x²+2.x.5+5²+y²+2.y.1+1²

=(x+5)²+(y+1)²

b)x^2 - 2xy + 2y^2 + 2y +1

=x²-2xy+y²+y²+2y+1

=(x-y)²+(y+1)²

c)z^2 - 6z + 13 + t^2 + 4t

=z²-6z+9+t²+4z+4

=z²-2.z.3+3²+t²+2.t.2+2²

=(z-3)²+(t+2)²

d)4x^2 + 2z^2 - 4xz - 2z + 1

=4x²-4xz+z²+z²-2z+1

=(2x)²-2.2x.z+z²+z²-2z.1+1²

=(2x-z)²+(z-1)²

a) x^2 + 10x + 26 + y^2 + 2y

=x²+10x+25+y²+2y+1

=x²+2.x.5+5²+y²+2.y.1+1²

=(x+5)²+(y+1)²

b)x^2 - 2xy + 2y^2 + 2y +1

=x²-2xy+y²+y²+2y+1

=(x-y)²+(y+1)²

c)z^2 - 6z + 13 + t^2 + 4t

=z²-6z+9+t²+4z+4

=z²-2.z.3+3²+t²+2.t.2+2²

=(z-3)²+(t+2)²

d)4x^2 + 2z^2 - 4xz - 2z + 1

=4x²-4xz+z²+z²-2z+1

=(2x)²-2.2x.z+z²+z²-2z.1+1²

=(2x-z)²+(z-1)²

a) (x-3)^2 - 4 =0

<=>(x-3)²-2²=0

<=>(x-3-2)(x-3+2)=0

<=>(x-5)(x-1)=0

<=>x-5=0 hoặc x-1=0

<=>x=5 hoặc x=1

b) x^2 - 2x = 24

<=>x²-2x-24=0

<=>x²-2x+1-25=0

<=>(x-1)²-25=0

<=>(x-1)²-5²=0

<=>(x-1-5)(x-1+5)=0

<=>(x-6)(x+4)=0

<=>x-6=0 hoặc x+4=0

<=>x=6 hoặc x=-4

a)  \(x^2-4x+5+y^2+2y=\left(x^2-4x+4\right)+\left(y^2+2y+1\right)\)

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

b)  \(2x^2+y^2-2xy+10x+25=\left(x^2+10x+25\right)+\left(x^2-2xy+y^2\right)\)

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

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

bạn ơi , bạn lấy bài này ở đâu vậy bạn

tớ ko biết

a) \(x^2+4x+4\)

\(=x^2+2\cdot2\cdot x+2^2\)

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

b) \(4x^2-4x+1\)

\(=\left(2x\right)^2-2\cdot2x\cdot1+1^2\)

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

c) \(x^2-x+\dfrac{1}{4}\)

\(=x^2-2\cdot\dfrac{1}{2}\cdot x+\left(\dfrac{1}{2}\right)^2\)

\(=\left(x-\dfrac{1}{2}\right)^2\)

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

\(=\left[2\left(x+y\right)\right]^2-2\cdot2\left(x+y\right)\cdot1+1^2\)

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

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

x² + 10x + 26 + y² + 2y
= x² + 10 + 25 + 1 + y² + 2y
= (x² + 10x + 25) + (y² + 2y + 1)
= (x + 5)² + (y + 1)²

x² - 2xy + 2y² + 2y + 1
= x² - 2xy + y² + y² + 2y + 1
= (x² - 2xy + y²) + (y² + 2y + 1)
= (x - y)² + (y + 1)²

4x² + 2z² - 4xz - 2z + 1
= 4x² + z² + z² - 4xz - 2z + 1
= (4x² - 4xz + z²) + (z² - 2z + 1)
= (2x + z)² + (z - 1)²

a) x²+10x+26+y²+2y

=x²+10x+25+y²+2y+1

=(x+5)²+(y+1)²

b) z²-6z+5-t²-4t

=z²-6z+9-t²-4t-4

=(z-3)²-(t²+4t+4)

=(z-3)²-(t+2)²

c)x²-2xy+2y²+2y+1

=x²-2xy+y²+y²+2y+1

=(x-y)²+(y+1)²

d) 4x²-12x-y²+2y+8

=4x²-12x+9-y²+2y-1

=(2x-3)²-(y²-2y+1)

=(2x-3)²-(y-1)²

bạn ơi , bạn lấy bài này ở đâu vậy bạn