How do you find the vertex of the parabola #y=x^2-2x-8#?

1 Answer
Jun 13, 2017

#(1,-9)#

Explanation:

#"for the standard form of a parabola " y=ax^2+bx+c#

#"the x-coordinate of the vertex is"#

#x_(color(red)"vertex")=-b/(2a)#

#y=x^2-2x-8" is in standard form"#

#"with " a=1,b=-2" and " c=-8#

#rArrx_(color(red)"vertex")=-(-2)/2=1#

#"substitute this value into the equation for y-coordinate"#

#rArry_(color(red)"vertex")=1-2-8=-9#

#rArrcolor(magenta)"vertex "=(1,-9)#
graph{x^2-2x-9 [-32.42, 32.53, -16.34, 16.15]}