SOLUTION: Equation of a Circle 7. The point (a, 8) lies on the circle defined by x^2+y^2=100. a) Explain why there are two possible values for a. Find these values. b) Use a graph to chec

Here is why there are two possible values:

When you substitute x=a and y=8 into



you get



Then you simplify and solve for .





But then when you take the square root, there
are two square roots of 36, and so you get:



which means these two answer:

 and 

You can see that both points (-6,8) and (6,8) are on
the circle 
Edwin