$x^2+2x-1$  

 $x^2-2x-1$  

 $x^2-1$  

BENAR / TRUE

PALSU / FALSE

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

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

14

5

$\left(x+2\right)\left(2x+1\right)$

$\left(x+1\right)\left(2x+2\right)$

$\frac{1}{2}\times3y\times4$

$\frac{1}{2}\times3y\times2$

$\frac{1}{2}\times4\times2$