Question #2a1a4

1 Answer
Mar 25, 2017

The inverse function is: g^-1(x)=21/(3-x)-7g1(x)=213x7. See explanation.

Explanation:

To find the inverse function you have to transform the formula of g(x)g(x) to calculate the value of xx in terms of yy:

y=(3x)/(x+7)y=3xx+7

y=(3x+21)/(x+7)-21/(x+7)y=3x+21x+721x+7

y=3-21/(x+7)y=321x+7

21/(x+7)=3-y21x+7=3y

1/(x+7)=(3-y)/211x+7=3y21

Now we can change the fractions to their reciprocals so that xx appears in the numerator:

x+7=21/(3-y)x+7=213y

x=21/(3-y)-7x=213y7

Now we can "rename" the argument and the value to write the formula using the standard convention (xx as the argument and yy as the function's value)

y=21/(3-x)-7y=213x7

Finally we can write the answer:

g^-1(x)=21/(3-x)-7g1(x)=213x7