The square of solution 5Y plus y is equal to 1 to find the solution of the equation

The square of solution 5Y plus y is equal to 1 to find the solution of the equation

Using the root formula 5Y ^ 2 + Y - 1 = 0
y = =[-b±√(b^2-4ac)]/(2a) = [-1 ±√(1+20)]/10 =