Add
- $6 x^{4}-9 x^{2}$ $\underline{7 x^{4}-9 x^{2}}$ A) $13 x^{8}-18 x^{4}$

Multiple Choice

Add.
- $6 x^{4}-9 x^{2}$
$\underline{7 x^{4}-9 x^{2}}$

A) $13 x^{8}-18 x^{4}$
B) $13 x^{4}-18 x^{2}$
C) $-5 x^{6}$
D) $-5 x^{12}$