Question

Solve the equation 3x2+7x−6=0
using the quadratic formula.

Graph of y = 3x² + 7x - 6 with red points on the curve.
(1 point)

The solution set is {-3, 2/3}.

The solution set is {-2, 1/3}.

The solution set is {3, -2/3}.

The solution set is {2, -1/3}.

Answer 1

Use x = [-b ± sqrt(b^2 − 4ac)]/(2a) with a = 3, b = 7, c = −6.

Discriminant: b^2 − 4ac = 49 − 4(3)(−6) = 49 + 72 = 121, sqrt = 11.

x = (−7 ± 11)/6 ⇒ x = (4)/6 = 2/3 or x = (−18)/6 = −3.

Solution set = {−3, 2/3}. (First choice.)