Applicare la formula: $x\left(a+b\right)$$=xa+xb$, dove $a=\frac{3x}{7}$, $b=-1$, $x=\frac{2mn}{5}$ e $a+b=\frac{3x}{7}-1$

Applicare la formula: $-\frac{b}{c}$$=\frac{expand\left(-b\right)}{c}$, dove $b=2mn$ e $c=5$

Applicare la formula: $\frac{a}{b}\frac{c}{f}$$=\frac{ac}{bf}$, dove $a=2mn$, $b=5$, $c=3x$, $a/b=\frac{2mn}{5}$, $f=7$, $c/f=\frac{3x}{7}$ e $a/bc/f=\frac{2mn}{5}\frac{3x}{7}$

Applicare la formula: $ab$$=ab$, dove $ab=5\cdot 7$, $a=5$ e $b=7$

Applicare la formula: $ab$$=ab$, dove $ab=2\cdot 3mnx$, $a=2$ e $b=3$