If 
= 18, find the values of 
and
.
x2 + 
= 18
Adding 2 on both sides, we get
x2 + 
+ 2 = 18 + 2
x2 + 
+ 2 × x × 
= 20
(x + 
)2 = 20
x + 
= 2
Given that,
x2 + 
= 18
Subtracting 2 from both sides, we get
x2 + 
- 2 × x × 
= 18 – 2
(x - 
)2 = 16
x - 
= 4
9