Hello,
y=2xe^x
y'=2(e^x+xe^x)=2(x+1)e^x
y''=2(e^x+(x+1)e^x)=2(x+2)e^x
x |-infinite -2 0 +infinite
e^x | ++++++++++++++++++
x+2 |------------0 +++++++++++
y'' | -----------0 +++++++++++
y''<0 if x<-2
<span>The interval on which the graph is concave down is (-infinite -2[</span>
I think the answer is Beth can make 8 dozen gingerbread men
You didn't give a graph but I will visualize what it looks like for you.
The line is going through (0,-2) because that is the y-intercept.
The line has a slope of 3.
So, the line goes through:
(1,1)
(2,4)
(3,7)
(4,10)
(5,13)