1. Given: x = 5 - 26
x1=5−261
⇒x1=(5−26)×(5+26)1×(5+26)=52−(26)25+26=25−245+26=5+26
Now, the value of x+x1 = (5+26)+(5−26)
= 5+26+5−26
= 10
Hence, the value of x+x1 = 10.
2. x+x1 = 10
Squaring both sides, we get
⇒(x+x1)2=102⇒x2+x21+2×x×x1=100⇒x2+x21+2=100⇒x2+x21=100−2⇒x2+x21=98
Hence, the value of x2+x21=98.