帮解2题文字题

(1)将x+1/x=7两边平方得x^2+1/x^2=（x+1/x)^2-2=49-2=47

（2）由(1)得x^2+1/x^2-4=（x-1/x）^2=43，所以x-1/x=正负根号43

sorry

1. x^2+1/x^2=(x^2+1/x^2)^2-2* x^2 * 1/x^2=49-2=47
2. x-1/x=(x-1/x)(x+1/x)/(x+1/x)=x^2-1/x^2=[(x^2+1/x^2)^2-4* * x^2 * 1/x^2]/7=(49-4)/7=45/7

解：
x+1/x=7
x+1=7x
x=1/6
(1) (x^2+1)/x^2
=(1/36+1)/(1/36)
=7
(2) (x-1)/x
=(1/6-1)/(1/6)
=5