What is the vertex form of # y = 3x^2 − 50x+300 #?

2 Answers
Apr 22, 2018

#y=3(x-25/3)^2+275/3#

Explanation:

#"the equation of a parabola in "color(blue)"vertex form"# is.

#color(red)(bar(ul(|color(white)(2/2)color(black)(y=a(x-h)^2+k)color(white)(2/2)|)))#

#"where "(h,k)" are the coordinates of the vertex and a"#
#"is a multiplier"#

#"obtain this form using "color(blue)"completing the square"#

#• " the coefficient of the "x^2" term must be 1"#

#"factor out 3"#

#rArry=3(x^2-50/3x+100)#

#• " add/subtract "(1/2"coefficient of the x-term")^2" to"#
#x^2-50/3x#

#y=3(x^2+2(-25/3)x color(red)(+625/9)color(red)(-625/9)+100)#

#color(white)(y)=3(x-25/3)^2+3(-625/9+100)#

#color(white)(y)=3(x-25/3)^2+275/3larrcolor(blue)"in vertex form"#

Apr 22, 2018

The vertex form of equation is #y=3(x-25/3)^2+1100/12#

Explanation:

#y=3 x^2-50 x+300 or y=3(x^2-50/3 x)+300# or

#y=3{x^2-50/3 x +(50/6)^2}-2500/12+300# or

#y=3(x-25/3)^2+1100/12# Comparing with vertex form of

equation #y = a(x-h)^2+k ; (h,k)# being vertex we find

here #h=25/3 , k=1100/12 :.# Vertex is at #(8.33,91.67) #

The vertex form of equation is #y=3(x-25/3)^2+1100/12#

graph{3 x^2-50 x+300 [-320, 320, -160, 160]} [Ans]