SOLUTION: Solve the system by the substitution method. x^2 + y^2 =12 y= squareroot of x I cannot for the life of me figure this problem out!

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Question 969638: Solve the system by the substitution method.
x^2 + y^2 =12
y= squareroot of x
I cannot for the life of me figure this problem out!
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Can you decide what to "substitute", and where? You are given two equations and plainly told, "solve by the substitution method".

What is that y= something.... ?


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You very well CAN expect two solutions or two points! (...Until you analyze the system more carefully). Trust your skills, and hopefully, trust your concepts, too.



system%28x%5E2%2By%5E2=12%2Cy=sqrt%28x%29%29-----Note that x%3E=0 is a requirement for the second equation.

x%5E2%2B%28sqrt%28x%29%29%5E2=12

x%5E2%2Bx-12=0, looks factorable...

%28x-3%29%28x%2B4%29=0------remember the necessary condition for x.
Solution for this quadratic now factored equation is
x=3 or x=-4.

Again, remember the necessary condition for that second equation of the system:
highlight%28x=3%29 or cross%28x=-4%29.