Which circle crosses the x–axis when graphed?

(x – 4)2 + (y + 7)2 = 64

(x – 5)2 + (y – 8)2 = 49

(x + 6)2 + (y – 7)2 = 36

(x + 4)2 + (y + 6)2 = 25

Question

Which circle crosses the x–axis when graphed?

 (x – 4)2 + (y + 7)2 = 64

 (x – 5)2 + (y – 8)2 = 49

 (x + 6)2 + (y – 7)2 = 36

 (x + 4)2 + (y + 6)2 = 25

asnaseer · Answer

think about the y-value when the circle crosses the x-axis.

what do you think y will equal at the points where the circle crosses the x-axis?

anonymous · Answer

Would it be the opposite of what x is? like if x is positive y is negative?

asnaseer · Answer

no - let me draw an example that might help you work out what y will equal at these points:
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