If you plotted the points, it is quite evident that it's an exponential function. You can see that it quickly "explodes" rapidly heading off to infinity.

Domain: (-inf, inf)

Range: (0, inf)

a.) x - 2*sqrt(x) = 0

-2*sqrt(x) = x

sqrt(x) = x/(-2)

Square both sides

x = x^2/4

4x = x^2

0 = x^2 - 4x

0 = x*(x - 4)

x = 0 V x = 4

b.) You should be able to graph y = x; it has a slope of 1 and y-intercept of 0. For y = 2*sqrt(x), plug in values and it will be evident what it looks like.

Note any negative values are undefined.

So, for instance, plot:

(0, 0)

(1, 2)

(4, 4)

(9, 6)

(16, 8)

.

.

.

The point of intersection is when the two graphs are equal.

This occurs at x = 0 ^ x = 4, and is very obvious by looking at a graph. Or, using algebra,

2*sqrt(x) = x

Which we solved earlier.