a. -7/3 b. 5 c. 3/14 d. -3/7 7/9/2014 | Rachel from Bastrop, TX | 2 Answers | 0 Votes Mark favorite Subscribe Comment
the x value for the vertex of a parabola is -b/2a =-3/(-2*7) = 3/14 is the answer, the derivation made by my colleague Piyushi L is perfect as well. 7/9/2014 | Francisco E. Comment
df(x) / dx should be 0 for the parabola f(x) at the vertex point df(x)/dx = -14x + 3 = 0 x = 3/14 Answer is c 7/9/2014 | PIYUSH L. Comment