\(N=\dfrac{2L}{3,4}=2400\left(nu\right)\)
\(H=N+G\rightarrow G=X=660\left(nu\right)\)
\(\rightarrow A=T=\dfrac{N}{2}-660=540\left(nu\right)\)
\(\left\{{}\begin{matrix}X_1+T_1=720\\X_1-T_1=120\end{matrix}\right.\rightarrow\left\{{}\begin{matrix}X_1=420\left(nu\right)\\T_1=300\left(nu\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}X_2=G_1=660-420=240\left(nu\right)\\T_2=A_1=540-300=240\left(nu\right)\end{matrix}\right.\)