(7+1)(7²+1)(7^4+1)(7^8+1)(7^16+1) домножим на (7-3)
(7-1)*(7+1)(7²+1)(7^4+1)(7^8+1)(7^16+1)=(7²-1)(7²+1)(7^4+1)(7^8+1)(7^16+1)=
(7^4-1)(7^4+1)(7^8+1)(7^16+1)=(7^8-1)*(7^8+1)(7^16+1)=(7^16-1)(7^16+1)=7^32-1
(7+1)(7²+1)(7^4+1)(7^8+1)(7^16+1)=(7^32-1)/(7-1)=(7^32-1)/6
1/6*7^32-(7^32-1)/6=1/6*7^32-1/6*7^32+1/6=1/6
х²=а⇒а²-3а+1=0
D=9-4=5
x1=(3-√5)/2 U x=(3+√5)/2
x²=(3-√5)/2U x²=(3+√5)/2
x^4-3x²+1=(x²-3+√5)(x²-3-√)