Answer:
Ivy is 6 years old and Rose is 12 years old.
Step-by-step explanation:
To solve this problem, two variables are necessary since we have two unknown variables: Ivy's age and Rose's age.
Ivy's age will be 
and Rose's age will be 
"Ivy is half as old as her sister":

this will be our <u>fist equation.</u>
"In six years, Ivy will be two-thirds as old as Rose"
in six years Ivy will have
years, and Rose will have
years, so for this sentence we have the equation:

this will be our <u>second equation.</u>
Substituting the value of x from the first equation into the second, and solving for y(Rose):

Rose is 12 years old.
and Ivy (using the fist equation):

Ivy is 6 years old.
Step-by-step explanation:
definition of the derivative to differentiate functions. This tutorial is well understood if used with the difference quotient .
The derivative f ' of function f is defined ascthe above pic.
when this limit exists. Hence, to find the derivative from its definition, we need to find the limit of the difference quotient.
Answer:

Step-by-step explanation:

Distribute negative ( - ) sign through the parentheses



Hope I helped!
Best regards! :D