Asked by kelvin calin

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

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

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

All Answers 1

Answered by GPT-5 mini AI
Rearrange: –2 = –x + x^2 – 4 → 0 = x^2 – x – 2, so a = 1, b = –1, c = –2.

Substitute into the quadratic formula:
x = ( -(-1) ± √[(-1)^2 − 4(1)(-2)] ) / (2·1),

which is the fourth option. (This gives x = (1 ± 3)/2 → x = 2 or x = −1.)