Take everything to one side and equate it to zero
So: 5x^2 -x -1=0
Next factorise so it’s 5(x^2-1/5)-1=0
So: 5(x-1/5) ^2 -1=0
So complete the square
First of all remove the five by division (x- ((1/5)/2)^2+ (1/5/2)^2 ) -1 =0
So (x- 1/10)^2 +1/5 +1/100 =0
Answer is (x-1/10)^2 -21/100 =0
Take -21/100 to the other side so:
(x-1/10)^2 = 21/100
Square root both sides so
(X-1/10) = square root of 21/100
Take -1/10 to the other side so
X= 1/10 + square root of 21/100
