Answer:
The differential equation is 
Step-by-step explanation:
Differential equation for the rate of change in radiation level:
Radiation level is R.
Rate of change indicates that the radiation level R varies in function of time t, which mathematically means that we have:

After the reactor is shut down, the radiation from the nitrogen-17 decreases in such a way that the rate of change in the radiation level is directly proportional to the radiation level.
Rate of change is k. Decreases means that k is negative. Proportional to the radiation level of R means that -k multiplies R. So the differential equation is:

That answer is x≤−8
Inequality:
8x−8≤−72
Step number 1: You have to Add 8 to both sides.
8x−8+8≤−72+8
8x≤−64
Step number 2: You have to Divide both sides by 8.
8x
/8 ≤ −64
/ 8
Ur Answer:
x≤−8
Hope this helps :)
7 apples = 4.55
To find the single cost of an apple, divide 4.55 by 7
4.55/7 = 0.65 per apple
Let's check to see if this is right.
0.65 x 7 = 4.55 = correct
0.65 x 9 = $5.85 for 9 apples
10,000-1,000=9,000 -100
8,900,i think maybe