(а²-4а+4)(а²+4а+4)-а²(а²-8)=16
(а²+4)²-16а²-а^4+8а²=16
а^4 +8а²+16-16а²-а^4 +8а²=16
8а²+16-16а²+8а²=16
8а²-16а²+8а²=0
0=0
(а²-4а+4)(а²+4а+4)-а²(а²-8)=16
(а²+4)²-16а²-а^4+8а²=16
а^4 +8а²+16-16а²-а^4 +8а²=16
8а²+16-16а²+8а²=16
8а²-16а²+8а²=0
0=0