Question

已知x的2次方减x加1分之x等于7,求x的4次方加x的2次方加1分之x的2次方的值？

Answer 1

x / (x² - x+1) = 7
(x² - x + 1) / x = 1/7
x - 1 + 1/x = 1/7
x + 1/x = 8/7
(x+ 1/x)² = 64/49
x² + 2 + 1/x² = 64/49
x² + 1 + 1/x² = 15/49
(x⁴+x²+1) / x² = 15/49
x² / (x⁴+x²+1) = 49/15,6,