Answer:

Step-by-step explanation:
Given;
x² - 2x - 1 = 0
Solve by completing the square method;
⇒ take the constant to the right hand side of the equation.
x² - 2x = 1
⇒ take half of coefficient of x = ¹/₂ x -2 = -1
⇒ square half of coefficient of x and add it to the both sides of the equation


⇒ take the square root of both sides;

Therefore, option B is the right solution.
10 1/2 x 2 2/3= 28, 3 1/3 x 4 2/7= 14.2857142857, 7/2 - 4/5= 2.7