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finding the domain of the rational function.

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f(x)=x^2-36/x^2-7x+6
Thanks.
asked Mar 14, 2014 in ALGEBRA 1 by mathgirl Apprentice

1 Answer

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The function is f(x) = (x2 - 36)/(x2 - 7x + 6).

Find the factors of denominator expression x2 - 7x + 6.

= x2 - 6x - x + 6

= x(x - 6) - (x - 6)

= (x - 1)(x - 6)

Find the factors of numerator expression x2 - 36.

= x2 - 62

Apply difference of squares : a2 - b2 = (a + b )(a - b ).

= (x + 6)(x - 6).

f(x) = (x2 - 36)/(x2 - 7x + 6) = [(x + 6)(x - 6)] / [(x - 1)(x - 6)] = (x + 6) / (x - 1).

f(x) = (x + 6) / (x - 1).

Domain excludes x - values that result in division by zero.

The function has an implied domain that consists of all real x other than x = 1.This value is excluded from the domain because division by zero is undefined.

answered Sep 4, 2014 by casacop Expert

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