Answer:
x = 5/2 + sqrt(17)/2 or x = 5/2 - sqrt(17)/2
Explanation:
Solve for x: 
x^2 - 5 x + 2 = 0 
 
Subtract 2 from both sides: 
x^2 - 5 x = -2 
 
Add 25/4 to both sides: 
x^2 - 5 x + 25/4 = 17/4 
 
Write the left hand side as a square: 
(x - 5/2)^2 = 17/4 
 
Take the square root of both sides: 
x - 5/2 = sqrt(17)/2 or x - 5/2 = -sqrt(17)/2 
 
Add 5/2 to both sides: 
x = 5/2 + sqrt(17)/2 or x - 5/2 = -sqrt(17)/2 
 
Add 5/2 to both sides: 
Answer: x = 5/2 + sqrt(17)/2 or x = 5/2 - sqrt(17)/2