D. because PQR and XYZ are not congruent
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.
3 sqrt (6) should be correct
Answer:
a = -24
Step-by-step explanation:
-a/6 +8 = 12
Subtract 8 from each side
-a/6 +8-8 = 12 -8
-a/6 = 4
Multiply by -6 on each side
-a/6 * -6 = 4*-6
a = -24