document.write( "Question 142577: We're trying to help our grandson with 8th grade algebra. Could you explain to me what domain means.(as in find domain of the function?) Sincerely, Teresa M. \n" ); document.write( "
Algebra.Com's Answer #103777 by stanbon(75887)\"\" \"About 
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Linear equation: y = 3x + 5
\n" ); document.write( "Domain: all Real Numbers
\n" ); document.write( "Why? x is an independent variable that can take on any Real value
\n" ); document.write( "unless there is some reason in the equation which restricts values
\n" ); document.write( "of x.
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\n" ); document.write( "Examples of restricted domains:
\n" ); document.write( "y = 3/(x+2)
\n" ); document.write( "x cannot take the value -2 because that would make the fraction
\n" ); document.write( "meaningless (Note: You cannot divide by zero)
\n" ); document.write( "Domain: All Real Numbers except x = -2
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\n" ); document.write( "y = sqrt(x-3)
\n" ); document.write( "The x-3 cannot be negative because the square root of a negative
\n" ); document.write( "is not a Real Number.
\n" ); document.write( "So x must be greater than or equal to 3.
\n" ); document.write( "Domain: All Real Numbers greater than or equal to 3.
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\n" ); document.write( "Comment: Those examples show the primary reasons for restricting
\n" ); document.write( "the domain:
\n" ); document.write( "1st: Denominators cannot zero
\n" ); document.write( "2nd: You cannot take the square root of a negative.
\n" ); document.write( "There are other conditions that restrict the Domain of a function
\n" ); document.write( "but I am assuming you are dealing with fundamentals of algebra.
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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