Applicare la formula: $x\left(a+b\right)$$=xa+xb$, dove $a=\frac{y}{2^n}$, $b=\frac{1}{2}$, $x=\frac{y}{2^n}-3$ e $a+b=\frac{y}{2^n}+\frac{1}{2}$

Applicare la formula: $x\left(a+b\right)$$=xa+xb$, dove $a=\frac{y}{2^n}$, $b=-3$, $x=\frac{y}{2^n}$ e $a+b=\frac{y}{2^n}-3$

Applicare la formula: $x\left(a+b\right)$$=xa+xb$, dove $a=\frac{y}{2^n}$, $b=-3$, $x=\frac{1}{2}$ e $a+b=\frac{y}{2^n}-3$

Applicare la formula: $\left(\frac{a}{b}\right)^n$$=\frac{a^n}{b^n}$, dove $a=y$, $b=2^n$ e $n=2$

Applicare la formula: $\frac{a}{b}\frac{c}{f}$$=\frac{ac}{bf}$, dove $a=1$, $b=2$, $c=y$, $a/b=\frac{1}{2}$, $f=2^n$, $c/f=\frac{y}{2^n}$ e $a/bc/f=\frac{1}{2}\frac{y}{2^n}$