Can you explain to me how to do this equation?

Describe the locus of points whose coordinates satisfy both statements:
x2 = 49
x2 + y2 = 85

Question

Can you explain to me how to do this equation?

Describe the locus of points whose coordinates satisfy both statements: 
x2 = 49 
x2 + y2 = 85

anonymous · Answer

$$x =\pm \sqrt{7}$$

anonymous · Answer

What about $$x2 + y2 =85?$$

anonymous · Answer

$$\pm7, \pm6$$

dumbcow · Answer

replace 49 with x^2
49+y^2 = 85
y^2 = 85-49 =36
y = +- 6
solution is (+-7,+-6)

anonymous · Answer

x^2=49
so
x^2+y^2=85
49+y^2=85,
y^2=85-49
y=+-6
x=+-7

anonymous · Answer

Great, so then if i plot that, how would i find my radius?  sorry to continue to ask questions!  By the way thank you everyone for all of your help!

anonymous · Answer

$$7^2+y^2=85$$$$y^2=85-49$$$$y^2= \sqrt{36}$$$$y=\pm6$$

anonymous · Answer

how do i find the radius?  or do i not need to?

dumbcow · Answer

x^2 +y^2 = r^2
therefore 
r^2 = 85
r = sqrt(85)

anonymous · Answer

THANK YOU!  That makes complete sense!

dumbcow · Answer

your welcome, its the same for all circles
(x-h)^2 + (y-k)^2 = r^2, (h,k) is center

anonymous · Answer

The locus is not a curve of a line. It is a set of four points
(7,6), (-7,6), (-7,-6) and (7,-6) and they are where
the lines  x=+-7 or y=+-6 meets the circle  x^2+y^2=85.

anonymous · Answer

I meant not a curve or line

anonymous · Answer

....lines meet the circle..