Answer:
Rate of change of the area of the square is 42 units at t = 2.
Step-by-step explanation:
We note that the area of the square is given by:
but we aim to find
. But we can use the chain rule to pull out that dA/dt. Doing so gives us:

Now,
(by the power rule and 
But since we have "x" and not "t", we want to find what x is when t = 2. Substituting t = 2 gives us x(2) = 3(2) + 1 = 7.
So, finally, we see that:

6b^2 + 9b + 11 is that in simplified form. I hope that it is what you were looking for :)
First divide -12 and 6
you should get -2.
now add that to 2.
-2 + 2 is 0
Answer:
Connor is 15, so we multiply Connor's age by 3, because that's how old Sadie is, but -5.
So our answer comes out to 40.
Sadie is 40 years old.
Glad i could help, have a nice day <3