move constant to other side add 1 4c^2-8c=1 divide by 4 to make leading coeficient 1 c^2-2c=1/4 take 1/2 of linear coeficient and square it -2/2=-1, (-1)^2=1 add that to both sides c^2-2c+1=1/4+1 factor perfect squaer and add (c-1)^2=5/4 square root both sides c-1=+/-(√5)/2 add 1 c=1+/-(√5)/2
