## College Algebra (10th Edition)

$a.\quad$see image $b.\quad$ The domain is $(-\infty,\infty)$ The range is $[-1,\infty)$ $c.\quad$ Decreasing on $(-\infty,-1)$ Increasing on $(-1,\infty)$
$f(x)=x^{2}+2x$ $a=1,b=2,c=0$ $a.\quad$ Leading coefficient is positive - opens up. Vertex: $x=\displaystyle \frac{-b}{2a}=\frac{-(2)}{2(1)}=\frac{-2}{2}=-1$ $f(-1)=-1$ Vertex: $(-1,1)$ Axis of symmetry: the line $x=-1$ Zeros $(x-$intercepts): $x^{2}+2x=0$ $x(x+2)=0$ $x=0$ or $x=-2$ $x-$intercepts: $(0,0),(-2,0)$ y-intercept: (0,c)$= (0,0)$ $b.\quad$ The domain is $(-\infty,\infty)$ The range is $[-1,\infty)$ $c.\quad$ Decreasing on $(-\infty,-1)$ Increasing on $(-1,\infty)$