The solution of a quadratic equation a x 2 + b x + c = 0 , using quadratic formula is given by − b ± √ b 2 − 4 a c 2 a Hence the solution of x 2 + 3 x + 1 = 0 is given by x = − 3 ± √ 3 2 − 4 ⋅ 1 ⋅ 1 2 ⋅ 1 or x = − 3 ± √ 9 − 4 2 = − 3 ± √ 5 2 Hence solution is given by irrational numbers − 3 + √ 5 2 and − 3 − √ 5 2 .
