## anonymous 4 years ago Please help...I don't know what to do or even where to start. Given the equation (x+3)^2+y^2=16 (a) find the center and the radius (b) graph (c) find the intercepts, if any.

1. anonymous

foil first

2. anonymous

(x+3)(x+3)

3. anonymous

x=-3 and y=0 center radius =4

4. asnaseer

the general equation of a circle is:$(x-a)^2+(y-b)^2=r^2$where (a,b) is the coordinate of the center of the circle, and r is its radius.

5. anonymous

|dw:1327549404656:dw|

6. anonymous

x when x=0 y= +-4

7. asnaseer

so if you rewrite your equation:$(x+3)^2+y^2=16$in the form you get:$(x-(-3))^2+(y-0)^2=4^2$from which you can see the center must be at (-3, 0) and the radius must be 4 as @cinar said above.

8. anonymous

I am sorry I made a mistake when x=0 y=+-sqrt7

9. anonymous

|dw:1327549640807:dw|

10. asnaseer

then, to find the intercepts you would do this: 1) x-intercept is when y=0, therefore:$(x+3)^2+0^2=16$$x+3=\sqrt{16}=\pm4$$x=1 \text{ or } -7$ 2) y-intercept is when x=0, therefore:$(0+3)^2+y^2=16$$9+y^2=16$$y^2=7$$y=\pm\sqrt{7}$

11. anonymous

this one is better than I drew http://www.wolframalpha.com/input/?i=plot+%28x%2B3%29^2%2By^2%3D16

12. anonymous

so if i have to go in and graph and i have to type in the #s into a box that looks like this 1 what do i type where Grid axis from to xaxis yaxis Interval xaxis y axis

13. anonymous

or what is the difference between the axis and the interval

14. anonymous

x axis is 1 and -7 interval is -7<=x<=1 y axis is sqrt7 and -sqrt7 but interval is -4<=y<=4 I dont know what grid is