Here, a = x2 , b = 2y2 , n = 7.
Now, n is odd.
\(\therefore\) \(\frac{n+1}2=\frac{7+1}2=4,\) \(\frac{n+3}2=\frac{7+3}2=5\)
\(\therefore\) Middle terms are t4 and t5 , for which r = 3 and r = 4 respectively.
\(\therefore\) Middle term are 280x8y6 and 560x6y8.