Solve for a:
a^2-2 a-1 = 0
Add 1 to both sides:
a^2-2 a = 1
Add 1 to both sides:
a^2-2 a+1 = 2
Write the left hand side as a square:
(a-1)^2 = 2
Take the square root of both sides:
a-1 = sqrt(2) or a-1 = -sqrt(2)
Add 1 to both sides:
a = 1+sqrt(2) or a-1 = -sqrt(2)
Add 1 to both sides:
Answer: | a = 1+sqrt(2) or a = 1-sqrt(2)
