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
