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:

Definitely A because it is the only one that makes sense
A) The dimensions are (x+10) by (x+10).
B) The perimeter is given by 4x+40.
C) The perimeter when x is 4 is 56.
The quadratic can be factored by finding factors of c, the constant, that sum to b, the coefficient of x. Our c is 100 and our b is 20; we want factors of 100 that sum to 20. 10*10=100 and 10+10=20, so those are what we need. This gives us (x+10)(x+10 for the factored form.
Since the dimensions are all (x+10), and there are 4 sides, the perimeter is given by 4(x+10). Using the distributive property we have 4*x+4*10=4x+40.
To find the perimeter when x=4, substitute 4 into our perimeter expression:
4*4+40=16+40=56.
I need to se the blanket to answer
Answer:
With all the lines, I may be wrong. But I'm confident that line B has a slope of 2.
This is because it rises up 2 up the y axis for every one unit on the x axis.