SOLUTION: Here's the question-determine whether the equation represents a function, the equation is y^2=x+9. If I isolate y, my equation becomes y=3*sq root of x and it graphs as a function

Question 27030: Here's the question-determine whether the equation represents a function, the equation is y^2=x+9. If I isolate y, my equation becomes y=3*sq root of x and it graphs as a function. The answer in the book says it's not a function because the equation is (y+1)^2=x. ????????
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
I think it's not a function.

y has two values for every value of x I put in the equation.
For it to be a function, there can be a single value of y for each x.
I can rewrite it as:

try y = +4

now y = -4

that's two values of y for one value of x.
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