Factor completely 16a^3b^7 + 2a^6 b4 − 22a ^4 b^5.

2(8a3b7 + a6b4 − 11a4b5)
2a3b4(8b3 + a3 − 11ab)
a3b4(16b3 + 2a3 − 22ab)
8b3 + a3 − 11ab