Answer:
Step-by-step explanation:
y > (1/3)x + 4 has an infinite number of solutions. Draw a dashed line representing y = (1/3)x + 4 and then pick points at random on either side of this line. For example, pick (1, 6). Substitute 1 for x in y > (1/3)x + 4 and 6 for y. Is the resulting inequality true? Is 6 > (1/3)(1) + 4 true? YES. So we know that (1, 6) is a solution of y > (1/3)x + 4. Because (1, 6) lies ABOVE the line y = (1/3)x + 4, we can conclude that all points abovve this line are solutions.
If 2 gallons of oil are used a day, than he will need 60 gallons of oil, because 30x2=60. For 60 gallons of oil, you would have to have 12 drums because 60÷5=12. Because there is already 8 drums of oil, there would already be 40 gallons because 8x5=40. If the owner already had 40 gallons of oil, they would only have to get 20 more gallons because 60-40=20. That would be 4 drums because 20÷5=4. The owner would have to order 4 more drums of oil.
You can see how this works by thinking through what's going on.
In the first year the population declines by 3%. So the population at the end of the first year is the starting population (1200) minus the decline: 1200 minus 3% of 1200. 3% of 1200 is the same as .03 * 1200. So the population at the end of the first year is 1200 - .03 * 1200. That can be written as 1200 * (1 - .03), or 1200 * 0.97
What about the second year? The population starts at 1200 * 0.97. It declines by 3% again. But 3% of what??? The decline is based on the population at the beginning of the year, NOT based no the original population. So the decline in the second year is 0.03 * (1200 * 0.97). And just as in the first year, the population at the end of the second year is the population at the beginning of the second year minus the decline in the second year. So that's 1200 * 0.97 - 0.03 * (1200 * 0.97), which is equal to 1200 * 0.97 (1 - 0.03) = 1200 * 0.97 * 0.97 = 1200 * 0.972.
So there's a pattern. If you worked out the third year, you'd see that the population ends up as 1200 * 0.973, and it would keep going like that.
So the population after x years is 1200 * 0.97x
