Question

Which equation has the solutions x=1+/-\sqrt 5? x2 + 2x + 4 = 0 x2 – 2x + 4 = 0 x2 + 2x – 4 = 0 x2 – 2x – 4 = 0

Answer 1

x^2 - 2x -4 =0

Using the quadratic formula -b +/- √b^2 - 4(ac) / 2a

Replace the letters with the values from the equation:

2 +/- √-2^2 -4*(1*-4) / 2*1

X = 2 +/- 2√5 / 2

x = 1 +/-√5

The answer is:  x^2 - 2x -4 =0