Solve the equation by completing the square.

2x^2 + 9x + 1 = 0

2 answers

x^2+9/2 x + 1/2 =0

x^2+9/2 x + 81/16 = 81/16 - 8/16

(x+9/4)^2= (1/4 sqrt 73)^2

x=+-1/4 sqrt73 -9/4
2x^2 +9x = -1

x^2 + 9x/2 +81/16 = -1/2 +81/16

(x +9/4)^2 = 73/16

x + 9/4 = -+sqrt(73/16)

x = (-9 - sqrt(73))/4

x = (-9 + sqrt(73))/4