1. Evaluate the function f(x) = 9x - 6 for x=0. 2. Bob owns a watch repair shop.
ID: 3105114 • Letter: 1
Question
1. Evaluate the function f(x) = 9x - 6 for x=0.2. Bob owns a watch repair shop. He has found that the cost of operating his shop is given by C(x) = 4x2-296x+85 , where c is cost and x is the number of watches repaired. How many watches must he repair to have the lowest cost?
3. Find the slope of the line through the points ( 5, -5) and ( 6, -1)
4. Kafka Inc. imports hard drives and sells them on the internet. The profit is given by the equation P = 140n - 8500, where n is the number of hard drives sold. Graph P = 140n - 8500 for n < 1000. Estimate the profit, to the nearest ten dollars, corresponding to the sale of 875 hard drives.
5. When $ 8500 is invested in a savings account paying simple interest for the year, the interest, i in dollars, can be obtained from the equation i = 8500r , where r is the rate of interest in decimal form. Graph i = 8500r , for r up to and including a rate of 16%. If the rate is 12%, how much interest is earned?
Explanation / Answer
1. When a problem says "evaluate the function for x = some value," that just means that you should plug that value in for x. So we will plug in 0 for x, giving us f(0) = 9(0) - 6 = 0 - 6 = -6 2. Here, we are looking to minimize the the cost function. If you're allowed to use a calculator, just plug in the function and find the minimum point, or the point at which the line intersects the x-axis (the lowest cost you can have is zero). 3. The formula for slope is the change in y over the change in x. (-5 - -1)/(6 - 5) = -4/1 = -4. There is a slope of -4. 4. In this case, graph the given equation on a calculator, and then try plugging in 875 for n. You should get P = 140(875) - 8500 = $114,000. 5. In this case, graph the given equation on a calculator, and then plug in .12 for r. in the equation. You should get i = 8500(.12) = $1020.
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