How do you complete the square to solve #x^2 - 8x + 13 = 0#?

Question

10904 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-05-30T11:50:59

In general the square #(x+a)^2 = x^2+2ax+a^2#

If #(-8x)# is the second term of a square of this form then
#a=-4# and #a^2=16#

#x^2-8x+13=0#

#(x-4)^2 -16 +13 = 0#

#(x-4)^2 = 3#

#x-4 = +-sqrt(3)#

#x = 4+-sqrt(3)#