# Functions : Domain and Range and X-intercepts

What are the domain and range and x intercepts of the function? Approximate to two decimal places.

y=-x^2-20x-3

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#### Solution Preview

Hi there.

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Domain is the set of x values for which the function is defined.

In this function, any value of x will evaluate to a number. Thus the domain of the function is all the real numbers.

As for the range - this is the set of values y can get.

The function is a parbola. Since the coefficient of x^2 is negative, this function is concave down and has a maxima (The minimal value is minus infinity, just plug in x=infinity or x=-infinity and you'll see).

To calculate the maxima, we take the first derivative ...

#### Solution Summary

The domain and range and x intercepts of a function are found.The solution is detailed and includes references.