Answer:
(C) (2, -2)
Step-by-step explanation:
Given the linear equation: 
A second linear equation is given by the table:
Clearly, this is a graph of y=-x as each y-value is a negative of its x-value.
Therefore if:
Recall: y=-x
Therefore: y= -2
Therefore, a solution to the system of equations is (2, -2)
Answer:
405 cm²/s
Step-by-step explanation:
The dimensions are increasing at the rate of 3 cm/s, so the dimensions in cm can be described as a function of time by ...
3 + 3t
and
6 + 3t
Then the area is the product of these, or ...
A = (3 +3t)(6 +3t)
A = 9t² +27t +18
and the rate of change of area is given by its derivative with respect to t:
A' = 18t +27
When t=21, the value of this is ...
A'(21) = 18·21 +27 = 405 . . . . cm²/s
