The intersection of two graphs

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Question from Jaqueline, a student:

Hi, can you help me this problem?
Find the points of intersection of the graphs of the equations

x^(2 )+ y^2=25 and 2x + y = 10

Jaqueline,

Solve the second equation for y

y = 10 - 2x.

Substitute this for y in the first equation

x² + (10 - 2x)² = 25

Simplify and solve the resulting quadratic for x. The resulting values of x are the x coordinates of the points of intersection.

I hope this helps,
Penny

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