SOLUTION: Solve this equation, one is simultaneous, one is linear x^2 + y^2 = 9 x + y = 3

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Question 1009260: Solve this equation, one is simultaneous, one is linear
x^2 + y^2 = 9
x + y = 3
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2+%2B+y%5E2+=+9.....eq.1
x+%2B+y+=+3.....eq.2
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start with
x+%2B+y+=+3.....eq.2 and solve for x
x+=+3-y.........eq.2a
substitute it in eq.1

%283-y%29%5E2+%2B+y%5E2+=+9.....eq.1 and solve for y
9-6y%2By%5E2+%2B+y%5E2+=+9
2y%5E2-6y%2B9++=+9
2y%5E2-6y=+9-9
2y%28y-3%29=+0
solutions:
if 2y=+0=>y=0
if %28y-3%29=+0=>y=3
go back to eq.2a, substitute y
x+=+3-y.........eq.2a if y=0
x+=+3-0
x+=+3

x+=+3-y.........eq.2a if y=3
x+=+3-3
x+=+0

so, we have two points of intersection of given lines and they are:
(3,0) and (0,3)