a²+b²=1
ab=12/25

(a-b)²=a²+b²-2ab
=1-2×12/25
=1/25
a-b=±1/5
(a+b)²=a²+b²+2ab
=1+2×12/25
=49/25
a+b=±7/5

a³-b³=(a-b)(a²+ab+b²)
=±1/5×(1+12/25)
=±37/125

a^4-b^4
=(a-b)(a+b)(a²+b²)
=±1/5*(±7/5)*1
=±7/25

a^6-b^6
=(a^3-b^3)(a^3+b^3)
=±37/125*(a+b)(a²-ab+b²)
=±37/125*(±7/5)*(1-12/25)
=±37/125*(±7/5)*13/25
=±3367/15625