What is the vertex of y= -3x^2 + 2x − 4?

2 Answers
May 21, 2018

vertex (1/3, -11/3)

Explanation:

a^2 + bx +c

y= -3x^2 + 2x − 4

a = -3
b=2
c=-4

vertex is (h, k)

h = (-b)/(2a)

k = f(h) i.e. put what you found for h back into your function as x and solve for y.

h = (-2)/(2*-3) = 1/3

k = (-3*1/3)^2 + 2*1/3 − 4 = -11/3

vertex (1/3, 1/3)

May 21, 2018

"vertex "=(1/3,-11/3)

Explanation:

"given the equation in standard form ";y=ax^2+bx+c

"then the x-coordinate of the vertex is"

•color(white)(x)x_(color(red)"vertex")=-b/(2a)

y=-3x^2+2x-4" is in standard form"

"with "a=-3,b=2" and "c=-4

rArrx_("vertex")=-2/(-6)=1/3

"substitute this value into the equation for y"

y=-3(1/3)^2+2/3-4

color(white)(y)=-1/3+2/3-12/3=-11/3

rArrcolor(magenta)"vertex "=(1/3,-11/3)