Question #21f0f
1 Answer
Nov 7, 2017
Explanation:
"given a parabola in standard form "color(white)(x);y=ax^2+bx+cgiven a parabola in standard form x;y=ax2+bx+c
"the x-coordinate of the vertex is"the x-coordinate of the vertex is
•color(white)(x)x_(color(red)"vertex")=-b/(2a)∙xxvertex=−b2a
y=-2x^2+4x+1" is in standard form"y=−2x2+4x+1 is in standard form
"with "a=-2,b=4,c=1with a=−2,b=4,c=1
rArrx_(color(red)"vertex")=-4/(-4)=1⇒xvertex=−4−4=1
"substitute this value into the equation for y"substitute this value into the equation for y
rArry_(color(red)"vertex")=-2+4+1=3⇒yvertex=−2+4+1=3
rArrcolor(magenta)"vertex "=(1,3)⇒vertex =(1,3)
graph{-2x^2+4x+1 [-10, 10, -5, 5]}
