What is the HCF of a 2 b 4 + 2 a 2 b 2 and (ab) 7 - 4a 2 b 2?

a² b⁴ + 2 a² b² = a² b² ( b² +2).......................(i)
and (ab)⁷ - 4 a² b⁹ = a⁷ b⁷ - 4 a² b⁹ = a² b²(a⁵ b⁵ - 4b⁷)................(ii)
from Eqs. (i) and (ii)
HCF = a² b²