Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
Concept Byte: Linear Programming
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Exercise 2 Page 163

The x and y that maximize the function is the point of intersection of the boundary lines.

x=5 and y=4

Practice makes perfect

We are asked to find the values of x or y that maximize the given function. Notice that the third set of constraints, x≥ 0 and y≥ 0, limit the solution set to the first quadrant. This means we should find the solution set of the first and second inequality in the first quadrant. Let's start by isolating y in each inequality.

3x+5y≤ 35 & (I) 2x+y≤ 14 & (II) x≥ 0, y≥ 0 & (III)
â–¼
(I), (II): Write in slope-intercept form
5y≤ - 3x+35 & (I) 2x+y≤ 14 & (II) x≥ 0, y≥ 0 & (III)
y≤ - 3x5+7 2x+y≤ 14 x≥ 0, y≥ 0
y≤ - 35x+7 2x+y≤ 14 x≥ 0, y≥ 0
y≤ - 35x+7 y≤ - 2x+ 14 x≥ 0, y≥ 0

To solve the system of inequalities we need to enter them in the calculator. Push Y= and write the functions in the first two rows.

Next, we have to set the calculator to account for the inequality. Place the cursor before Y and scroll by pushing ENTER. We will select the icon that displays a black triangle pointing down and to the left. This tells the calculator that we are dealing with a ≤ inequality.

With the inequalities entered in the calculator, we can graph them by pushing GRAPH. Before we do that let's limit the window to the first quadrant, as we have already established that we are interested in this area only.

The objective function is maximized where the boundary lines of the two inequalities intersect. We can use the calculator to find this point of intersection. To do this, push CALC (2nd + TRACE) and choose the fifth option in the list, intersect.

Now we must provide the calculator with some guesses as to where the intersection occurs.

The solution is x=5 and y=4. These values maximize the objective function.