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

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

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

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

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

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

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

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

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

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

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

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

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

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

$\left(a+b+c\right)\left(a+b-c\right)=\left(a+b\right)^2-c^2$

$2-a=\left(\sqrt{2}+a\right)\left(\sqrt{2}-a\right)$

$x-2=\left(\sqrt{x}-\sqrt{2}\right)\left(\sqrt{x}+\sqrt{2}\right)$

$\left(c+d\right)^2-\left(a+b\right)^2=\left(c+d+a+b\right)\left(c+d-a+b\right)$

$\left(c-d\right)^2-\left(a+b\right)^2=\left(c-d+a+b\right)\left(c-d-a+b\right)$

$\left(a+b+c-d\right)\left(a+b-c+d\right)=\left(a+b\right)^2-\left(c-d\right)^2$

$\left(c-d\right)^2-\left(a-b\right)^2=\left(c-d+a-b\right)\left(c-d-a-b\right)$

$\left(c-d\right)^2-\left(a-b\right)^2=\left(c-d+a-b\right)\left(c-d-a+b\right)$

 $A^2+2AB-B^2$  

 $A^2+2AB+B^2$  

 $A^2-2AB+B^2$  

 $A^2-2AB-B^2$  

 $x^2+9$  

 $x^2+6x+9$  

 $4x^2-4x+1$  

 $4x^2+4x-1$  

 $9-6x+4x^2$  

 $9+12x+4x^2$  

 $4x^2-12x+9$  

 $9-12x+x^2$  

 $2x^2+x+\frac{1}{2}$  

 $4x^2+4x+\frac{1}{2}$  

 $4x^2+2x+\frac{1}{4}$  

 $2x^2+x+\frac{1}{4}$  

 $9+4x^2$  

 $9-4x^2$  

 $9-12x\ +4x^2$  

 $9+12x+4x^2$  

 $\left(x-\frac{1}{2}\right)^2$  

 $\left(x+\frac{1}{2}\right)^2$  

 $\left(x-\frac{1}{2}\right)\left(x+\frac{1}{2}\right)$  

 $x^2-\left(\frac{1}{2}\right)^2$  

đúng

sai

(4y+4z)²

(16y+16z)²

(4y+16z)²

(16y+4z)²

(6 + x)²

(x + 36)²

(x + 3)(x + 4)

x(x + 12) - 36

(x + 1)(x - 3)

(x + 3)(x + 1)

(x - 1)(x - 3)

(x + 3)(x - 1)

 $2x^2+x+\frac{1}{2}$  

 $4x^2+4x+\frac{1}{2}$  

 $4x^2+2x+\frac{1}{4}$  

 $2x^2+x+\frac{1}{4}$