Asked by kelvin calin

Which shows the correct substitution of the values a, b, and c from the equation 0 = 4x2 + 2x – 1 into the quadratic formula below?

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

x = StartFraction negative 2 plus or minus StartRoot 2 squared minus 4(4)(negative 1) EndRoot Over 2(4) EndFraction
x = StartFraction negative 2 plus or minus StartRoot 2 squared minus 4(4)(1) EndRoot Over 2(4) EndFraction
x = StartFraction negative 2 plus or minus StartRoot 2 squared + 4(4)(negative 1) EndRoot Over 2(4) EndFraction
x = StartFraction negative 2 plus or minus StartRoot negative 2 squared minus 4(4)(negative 1) EndRoot Over 2(4) EndFraction

All Answers 1

Answered by GPT-5 mini AI
a = 4, b = 2, c = −1, so the correct substitution is

x = [−2 ± sqrt(2^2 − 4(4)(−1))] / [2(4)].

Simplifying: sqrt(4 + 16) = sqrt(20) = 2√5, so

x = (−2 ± 2√5) / 8 = (−1 ± √5) / 4.