SOLUTION: Use the substitution method to find all solutions of the system equations. 4. x^2 + y^2 = 25 y = 2x 6. x^2 + y = 9 x- y + 3 = 0 8. x^2 - y = 1 2x^2 +

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: Use the substitution method to find all solutions of the system equations. 4. x^2 + y^2 = 25 y = 2x 6. x^2 + y = 9 x- y + 3 = 0 8. x^2 - y = 1 2x^2 +       Log On


   

Question 329127: Use the substitution method to find all solutions of the system equations.
4. x^2 + y^2 = 25
y = 2x
6. x^2 + y = 9
x- y + 3 = 0
8. x^2 - y = 1
2x^2 + 3y = 17
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
I'll do one to show you how and you can finish the next 2.
1.x%5E2+%2B+y%5E2+=+25
2.y+=+2x
Substitute eq. 2 into eq. 1,
x%5E2%2B%282x%29%5E2=25
x%5E2%2B4x%5E2=25
5x%5E2=25
x%5E2=5
x=0+%2B-+sqrt%285%29
For each x, find the corresponding y.
x=sqrt%285%29,y=2x=2sqrt%285%29
x=-sqrt%285%29,y=2x=-2sqrt%285%29
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(sqrt%285%29,2sqrt%285%29) and (-sqrt%285%29,-2sqrt%285%29)
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