Simplify 4n^5+3.5n^5+(-2.1n^5)

$4 n^{5} + 3.5 n^{5} + (- 2.1 n^{5})$

Remove parentheses.

$4 n^{5} + 3.5 n^{5} - 2.1 n^{5}$

Add $4 n^{5}$ and $3.5 n^{5}$ .

$7.5 n^{5} - 2.1 n^{5}$

Subtract $2.1 n^{5}$ from $7.5 n^{5}$ .

$5.4 n^{5}$