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Sorry, ignore the other question I had on here, that was a typo. How do you find the positive/negative intervals of f(x) = 3/(x + 5) ? Please show in full detail!!

User Astrophage
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Answer:

Positive interval: x is in (-5, infty)

Negative interval: x is in (-infty, -5)

Explanation:

A fraction is positive when the numerator and denominator have the same sign. Since the numerator is positive in this case, the fraction will be positive when it's denominator is also positive. Thus, we need to solve x+5>0. Subtracting 5 on both sides gives x>-5.

Positive interval: x is in (-5, infty)

A fraction is is negative when the numerator and denominator have the different signs. Since the numerator is positive in this case, the fraction will be negative when it's denominator is negative. Thus, we need to solve x+5<0. Subtracting 5 on both sides gives x<-5.

Negative interval: x is in (-infty, -5)

A fraction doesn't have an output when it's denominator is 0. That is, in this case when x+5=0 which is when x is -5.

User Rgthree
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