What is the vertex of #y= -2x^2 + 2x + 9 #?
1 Answer
Jun 13, 2018
Explanation:
#"given a quadratic in standard form"#
#y=ax^2+bx+c;a!=0#
#"then the x-coordinate of the vertex is"#
#•color(white)(x)x_(color(red)"vertex")=-b/(2a)#
#y=-2x^2+2x+9" is in standard form"#
#"with "a=-2,b=2" and "c=9#
#x_("vertex")=-2/(-4)=1/2#
#"substitute this value into the equation for y"#
#y_("vertex")=-2(1/2)^2+2(1/2)+9=19/2#
#color(magenta)"vertex "=(1/2,19/2)#
