Question

Joline is solving the equation 0 = x2 – 5x – 4 using the quadratic formula. Which value is the negative real number solution to her quadratic equation? Round to the nearest tenth if necessary.



Quadratic formula: x = StartFraction negative b plus or minus StartRoot b squared minus 4 a c EndRoot Over 2 a EndFraction

–5.7
–4
–1
–0.7

Answer 1

Use a = 1, b = -5, c = -4.
x = [5 ± sqrt(25 + 16)]/2 = [5 ± sqrt(41)]/2.
The negative root is (5 - sqrt(41))/2 ≈ -0.7016 ≈ -0.7.