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Here are a few recommended readings before getting started with this lesson.
x | y=∣3x−6∣+3 | y |
---|---|---|
0 | y=∣3(0)−6∣+3 | 9 |
1 | y=∣3(1)−6∣+3 | 6 |
2 | y=∣3(2)−6∣+3 | 3 |
3 | y=∣3(3)−6∣+3 | 6 |
4 | y=∣3(4)−6∣+3 | 9 |
Plot the points and draw the boundary line. Since the given inequality is strict, the boundary line will be dashed.
x=0, y=0
Zero Property of Multiplication
Subtract terms
∣-6∣=6
The test point is not a solution, so the region that does not contain the test point — inside the V-shaped graph — represents the solution set for the inequality. Finally, the appropriate region can be shaded.
Analyze the graph of the given absolute value inequality in two variables to determine the proper inequality symbol.
LHS+4=RHS+4
a=22⋅a
Factor out 25
∣a⋅b∣=∣a∣⋅∣b∣
∣∣∣∣∣25∣∣∣∣∣=25
a=-(-a)
x | -25∣x+2∣+4 | y=-25∣x+2∣+4 |
---|---|---|
-4 | -25∣-4+2∣+4=-1 | -1 |
-3 | -25∣-3+2∣+4=1.5 | 1.5 |
-2 | -25∣-2+2∣+4=4 | 4 |
-1 | -25∣-1+2∣+4=1.5 | 1.5 |
0 | -25∣0+2∣+4=-1 | -1 |
Finally, plot the points and draw the absolute value equation.
As can be seen, the mirror has a V-shape with a vertex of (-2,4) in the coordinate plane.
x | y=0.4∣x−4∣+3 | y |
---|---|---|
0 | y=0.4∣0−4∣+3 | 4.6 |
2 | y=0.4∣2−4∣+3 | 3.8 |
4 | y=0.4∣4−4∣+3 | 3 |
6 | y=0.4∣6−4∣+3 | 3.8 |
8 | y=0.4∣8−4∣+3 | 4.6 |
Plot the points and draw the boundary line. Since the inequality is non-strict, the boundary line will be solid. Note that only positive values of x and y makes sense in the context of the situation.
Next, the region to be shaded will be determined. To do so, choose an arbitrary point not on the boundary line and substitute it into the inequality. Let the point be (0,0). Since 0≥4.6 is a false statement, it is not a solution to the inequality. Therefore, the region that does not contain the test point should be shaded.In the same auction, Emily was also interested in the object that Ignacio bought. Emily knows that Ignacio will sell it sooner or later. The maximum amount of money Emily can allocate to buy Ignacio's object is represented by the following graph.
Emily can use any amount less than $3800 for the object 4 years after the auction. Write an inequality to describe the given graph.To write the equation of the boundary line, use the vertex form of an absolute value equation y=a∣x−h∣+k, where (h,k) is the vertex of the absolute value equation.
On the given graph, x represents the years after the auction and y represents the price of the object in thousands of dollars. Since Emily can allocate any amount less than $3800 for the object 4 years after the auction, these values correspond to point (4,3.8), which is the vertex of the boundary line.
Recall the general form of an absolute value equation whose vertex is at (h,k).x=10, y=5
Subtract term
∣6∣=6
LHS−3.8=RHS−3.8
LHS/6=RHS/6
Rearrange equation
less than,<.
Any point in this region is the solution to both inequalities. In the context of the last two examples, Ignacio and Emily can make a deal as long as the values stay in that region.