(x²-5x+7)²- (x²-5x+7)=0

( х^2 - 5х + 7 )^2 - ( х^2 - 5х + 7 ) = 0
( х^2 - 5х + 7 ) = а
а^2 - а = 0
а( а - 1 ) = 0
а1 = 0
а2 = 1
1) х^2 - 5х + 7 = 0
D = 25 - 28 = - 3 ; < 0 ; корней нет
2) х^2 - 5х + 7 = 1
Х^2 - 5х + 6 = 0
D = 25 - 24 = 1 = 1^2
X1 = ( 5 + 1 ) : 2 = 3
X2 = ( 5 - 1 ) : 2 = 2
Ответ 3 ; 2