Applicare la formula: $\left(a+b\right)^3$$=a^3+3a^2b+3ab^2+b^3$, dove $a=\frac{2}{5}x^5$, $b=-\frac{5}{4}x$ e $a+b=\frac{2}{5}x^5-\frac{5}{4}x$

Applicare la formula: $\left(ab\right)^n$$=a^nb^n$

Applicare la formula: $x\cdot x^n$$=x^{\left(n+1\right)}$, dove $x^nx=-\frac{15}{4}\cdot \frac{4}{25}x^{10}x$, $x^n=x^{10}$ e $n=10$

Applicare la formula: $\frac{a}{b}\frac{c}{f}$$=\frac{ac}{bf}$, dove $a=-15$, $b=4$, $c=4$, $a/b=-\frac{15}{4}$, $f=25$, $c/f=\frac{4}{25}$ e $a/bc/f=-\frac{15}{4}\cdot \frac{4}{25}x^{11}$