F(x)=x^2 +6x-8 Find range of f I found the range correctly as -17 but I don't know that where should be inequality sign direction?
1 Answer
May 3, 2018
Explanation:
"we require to find the vertex of the parabola and establish"
"if it is a maximum or minimum"
"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"
"to obtain this form "color(blue)"complete the square"
rArry=x^2+2(3)x color(red)(+9)color(red)(-9)-8
rArry=(x+3)^2-17larrcolor(red)"in vertex form"
rArrcolor(magenta)"vertex "=(-3,-17)
"since "a>0" then minimum "uuu
"range is "y inRR,y>=-17
y in[-17,oo)larrcolor(blue)"in interval notation"
graph{x^2+6x-8 [-40, 40, -20, 20]}
