How do you find the domain of #f(x)=-x^2-5x+6#?

1 Answer
Kilwee
Jul 31, 2017

It's a polynomial function, so the domain is all real numbers, #RR#.

Explanation:

Since this equation is a polynomial function (quadratic functions are polynomial) its domain includes all real numbers, #RR#.

In general, to find the domain of a function you would have to find which values of #x# are restricted, meaning they would give an indefinite #y# or #f(x)#.

A restricted #x# value would usually arise in a case such as:
#f(x) = (3x^2 + 2)/(x-1)#
where an #x# value of 1 would give a denominator of 0, yielding an indefinite value for #f(x)#. Then, #x=1# is a restricted value.

But in this case, any real value of #x# will give a real value of #f(x)#, so the domain includes all real numbers.

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