a6 ⋅ (а ⋅ а2)2 = * ⋅ (-а4)
a6 ⋅ (а1+2)2 = * ⋅ (-а4)
a6 ⋅ (а3)2 = * ⋅ (-а4)
a6 ⋅ а3⋅2 = * ⋅ (-а4)
a6 ⋅ а6 = * ⋅ (-а4)
а6+6 = * ⋅ (-а4)
а12 = * ⋅ (-а4)
* = а12 : (-а4)
* = -а12-4
* = -а8
Ответ: -a8