SOLUTION: How would you find the points that the graphs of the equation in the following systems have in common? x^2+y^2=4 x=y

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Question 89877: How would you find the points that the graphs of the equation in the following systems have in common?
x^2+y^2=4
x=y

Found 2 solutions by jim_thompson5910, checkley75:
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Plug in y=x

Combine like terms


Divide both sides by 2

Take the square root of both sides

So our solutions are (,) and (,)


Check:




works

or





works



We can also verify with this graph



and if you used Pythagoreans theorem, you would verify your answer.

Answer by checkley75(3666)   (Show Source): You can put this solution on YOUR website!
FIRST I WOULD PLOT THEM & SEE IF THERE IS ANY OBVIOUS SOLUTION.
(graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions y = x and y^2 = -x^2
+4).
OR SET X=Y & SOLE FOR Y IN THE FIRST EQUATION
Y^2+Y^2=4
2Y^2=4
Y^2=4/2
Y^2=2
Y=+/-1.414 ANSWER.
X=Y=+/-1.414 ANSWER.

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