SOLUTION: what is the total number of points of intersection in the graphs of the equations x2+y2=16 and y=3?

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Question 252878: what is the total number of points of intersection in the graphs of the equations x2+y2=16 and y=3?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
the graphs of these two equations is shown below:

graph+%28600%2C600%2C-5%2C5%2C-5%2C5%2C3%2Csqrt%2816-x%5E2%29%2C-sqrt%2816-x%5E2%29%29

looks like there are 2 points of intersection.

you could solve for these by taking the equation of x^2 + y^2 = 16 and substituting 3 for y and then solving for x.

x^2 + y^2 = 16 becomes:

x^2 + (3)^2 = 16 becomes:

x^2 + 9 = 16 becomes:

x^2 = 16-9 = 7 becomes:

x = +/- sqrt(7) which is roughly 2.65 (more accurately shown as 2.645751311).

you can see on the graph that y = 3 intersection points roughly correspond to x = +/- 2.65.