Question

need help with coordinate points.

Answer 1

A circular pond is modeled by the equation x^2+y^2=25. A bridge over the pond is modeled by a segment of the equation y-x=-1. What are the coordinates of the points where the bridge meets the edge of the pond?

Answer 2

x^2+y^2=25
y-x=-1
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You will need to solve these two equations. (simultaneous solution)

Answer 3

I use substitution?

Answer 4

Actually, disregard my last comment.

Answer 5

Try substitution:

x^2+y^2=25
y-x=-1
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If y - x = -1, then

y = -1 + x

For y in x^2+y^2=25, substitute (-1 + x).

So, you would get:

x^2 + (-1 + x)^2 = 25

Solve that equation for x to get the x-coordinates of where the bridge meets the pond edge.

Answer 6

If you are allowed to use technology, you can use the "Wolf" to help solve the equations.
Click here:

http://www.wolframalpha.com/input/?i=x%5E2%2By%5E2%3D25%2C++y-x%3D-1

Answer 7

If that is not allowed, then we will need to crank out the solution ourselves. @Laxmath

Answer 8

Oh, so you do use substitution! Thanks!!!

Answer 9

You are welcome.