### Real(ly) Numbers

If x, y and z are real numbers such that: x + y + z = 5 and xy + yz + zx = 3. What is the largest value that any of the numbers can have?

### How Many Solutions?

Find all the solutions to the this equation.

Sketch the graphof $y=x^2$. If you exchange $x$ and $y$ the point $(a,b)$ on one graph has an image $(b,a)$ on the other graph. What transformation of the graphs will have this effect? What do you expect the graph of $x= y^2$ to look like? Find these two graphs on the illustration.