SOLUTION: x2 + y2 = 9 x + y = 2

Question 972799: x2 + y2 = 9
x + y = 2
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
x2 + y2 = 9
x + y = 2
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Use ^ (Shift 6) for exponents.
x^2 + y^2 = 9
x + y = 2 --> y = 2-x
Sub for y
----
x^2 + (2-x)^2 = 9
2x^2 - 4x - 5 = 0

Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=56 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 2.87082869338697, -0.870828693386971. Here's your graph:

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x = 1 - sqrt(14)/2
y = 2-x = 1 + sqrt(14)/2
===============
x = 1 + sqrt(14)/2
y = 2-x = 1 - sqrt(14)/2
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