Answer:
I think it is D
Step-by-step explanation:
Its saying that f of x is four times x. So if x was one it could be four. But if x was greater than one it would be higher than one. Therefore, I think that the answer should be all real numbers greater than or equal to four.
Hope this helped!!! Let me know if I was correct. Haven't done this in years.
Answer:

Step-by-step explanation:
For each right-angled triangle:

Because 
we have an equation

multiplying both sides by x, we get 
dividing both sides by 0.4 and 
using calculator, we divide 12 by 0.4
and finally x=30
You would need 3 cups of flour because 1*2 is 2 and 2*3 is 6 and 6 divided by 2 is 3
Answer is in the attachment below.
Step-by-step explanation:
use mathaway! it helps a lot