A line and a circle intersect at $A$ and $B,$ as shown below. Find the distance between $A$ and $B$. The circle is x^2 + y^2 = 20. The line is y = -4.
x^2 + (-4)^2 = 20
x^2 + 16 = 20
x^2 = 4
x = 2 x = -2
A = (2, -4) B = (-2 , -2)
AB = 2 - (-2) = 4
+1234 
