Answer:
it should be 6 not 100% sure though
Step-by-step explanation:
1 / y^7
Y^-9•y^-8•y^10
= y^10 / y^9•y^8
= y^10 / y^17
= 1 / y^7
8.11 and 9 1/11
B. -4
-16 + 12 = -4