You can
put this solution on YOUR website!f(x)=sqrt(x-8)
All real numbers >=8 sqrt of negative numbers are not real (imaginary).

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h(x)=3x^2+5x-3
all real numbers.

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m(x)=5/(x^2-9)
5/(x+3)(x-3)
All real numbers except when x=3 or x=-3 (division by zero not allowed)

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l(x)=5x-4
All real numbers.

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g(x)=7x+4/x+4
All real numbers except x=-4 (division by zero not allowed)

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Ed