Determine the roots.

Question

determine the roots of the quadratic equation.(complete the square) express your answer in exact values.

5x²+20x-1=0

Answer 1

5x² + 20x - 1 = 0

5(x² + 4x) - 1 = 0

5(x² + 4x + 4) - 20 - 1 = 0

5(x+2)² - 21 = 0 

5(x+2)² = 21

(x+2)² = 21/5 

x + 2 = ±√(21/5) 

x = -2 ±√(21/5)