What is the vertex of # y=x^2-3x-21#?
1 Answer
Jun 4, 2018
Explanation:
#"given a parabola in "color(blue)"standard form ";ax^2+bx+c#
#"then the x-coordinate of the vertex is"#
#•color(white)(x)x_(color(red)"vertex")=-b/(2a)#
#x^2-3x-21" is in standard form"#
#"with "a=1,b=-3" and "c=-21#
#x_("vertex")=-(-3)/2=3/2#
#"substitute this value into the equation for y"#
#y_("vertex")=(3/2)^2-3(3/2)-21=-93/4#
#color(magenta)"vertex "=(3/2,-93/4)#
