Question

How do I solve this by completing the square: (r^2) - 2r - 1 = 0

Answer 1

first thing move the -1 to the RHS
add on both sides the square of half of 2
what do you get?

Answer 2

(r^2) - 2r = 1

Answer 3

That is all I understand so far

Answer 4

what's half of 2?

Answer 5

1

Answer 6

(r^2) - 2r + (1^2) = 1 + (1^2)

Answer 7

good
r^2-2r+1=2
the left handside is a remarkable identity
(r-1)^2=2
can you now solve it?

Answer 8

Do you just square the RHS?

Answer 9

no i just added

Answer 10

No, I mean is that what you do next?

Answer 11

i hope you know that if x^2=a then x=sqrt(a) or x=-sqrt(a)

Answer 12

good,you got it

Answer 13

Thanks!

Answer 14

yw,don't forget to move the -1 to the RHS

Answer 15

Yep :)