Solution:
Given:

Since b and d are nonzero elements, then it is the product of two rational numbers.
Multiplying two rational numbers produces another rational number.
Therefore, the product is a rational expression.
OPTION C is the correct answer.
Answer:
y = 4
since you cant have y = 0x + 4, you drop the x and have a straight line (slope of 0) that runs all along the y point of 4.
Karl did because $58 for 20 pieces is cheaper than $63 for 21 and $3 for 21 pieces.
Answer:
Scenario A: Survey
Scenario B: Observational Studies
Scenario C: Experiment
Scenario D: Survey
If it not the answer you can correct me