Math Problem Statement

Sketch the region that corresponds to the given inequality. 4x-y<or equal to 1 and x + 2y< or equal to 7. Say whether the region is bounded or unbounded. Find the coordinates of all corner points (if any). (If an answer does not exist, enter DNE.) (x,y)=?

Solution

Step 1: Interpret the Inequalities

We are given the inequalities:

  1. 4xy14x - y \leq 1
  2. x+2y7x + 2y \leq 7

The solution set consists of all points (x,y)(x, y) that satisfy both inequalities.


Step 2: Convert Inequalities to Equations

To sketch the region, we first find the boundary lines by replacing the inequalities with equalities:

  1. 4xy=14x - y = 1 → (Equation of Line 1)
  2. x+2y=7x + 2y = 7 → (Equation of Line 2)

We will graph these lines and determine the region that satisfies both inequalities.


Step 3: Find Intersection of the Two Lines

To find the corner points, solve the system:

Solve for yy

  1. Solve for yy in terms of xx from the first equation: y=4x1y = 4x - 1
  2. Substitute into the second equation: x+2(4x1)=7x + 2(4x - 1) = 7 x+8x2=7x + 8x - 2 = 7 9x=99x = 9 x=1x = 1

Find yy

y=4(1)1=3y = 4(1) - 1 = 3 So, the intersection point is (1,3)(1,3).


Step 4: Find x- and y-Intercepts

For 4xy=14x - y = 1

  1. x-intercept (y=0y = 0):
    4x0=1x=144x - 0 = 1 \Rightarrow x = \frac{1}{4} Point: (14,0)\left(\frac{1}{4}, 0\right)

  2. y-intercept (x=0x = 0):
    4(0)y=1y=14(0) - y = 1 \Rightarrow y = -1 Point: (0,1)(0, -1)

For x+2y=7x + 2y = 7

  1. x-intercept (y=0y = 0):
    x+2(0)=7x=7x + 2(0) = 7 \Rightarrow x = 7 Point: (7,0)(7, 0)

  2. y-intercept (x=0x = 0):
    0+2y=7y=720 + 2y = 7 \Rightarrow y = \frac{7}{2} Point: (0,72)\left(0, \frac{7}{2}\right)


Step 5: Determine the Region

The solution region is the intersection of the two half-planes:

  • 4xy14x - y \leq 1 means the region is below the line y=4x1y = 4x - 1.
  • x+2y7x + 2y \leq 7 means the region is below the line y=7x2y = \frac{7 - x}{2}.

By shading the correct region in a graph, we see that the feasible region is bounded by the intersection points.


Step 6: Find Corner Points

The corner points of the bounded region are the intersections of the lines and axes:

  1. (1,3)(1,3) (Intersection of both lines)
  2. (7,0)(7,0) (x-intercept of x+2y=7x + 2y = 7)
  3. (14,0)\left(\frac{1}{4},0\right) (x-intercept of 4xy=14x - y = 1)

Thus, the corner points are: (14,0),(7,0),(1,3)\left( \frac{1}{4}, 0 \right), (7, 0), (1,3)


Final Answers

  1. Sketch: Graph the lines 4xy=14x - y = 1 and x+2y=7x + 2y = 7. Shade the intersection region.
  2. Bounded or Unbounded: Bounded
  3. Corner Points:
    (14,0),(7,0),(1,3)\left( \frac{1}{4}, 0 \right), (7, 0), (1,3)

Would you like me to generate a graph for visualization?


Further Exploration Questions

  1. How do we determine whether a region is bounded or unbounded?
  2. What happens if the inequalities were strict (i.e., << instead of \leq)?
  3. How does changing the coefficients of xx or yy in the inequalities affect the graph?
  4. Can you find the area of the bounded region?
  5. What are some real-world applications of solving systems of linear inequalities?

Tip:

To check whether a point is in the solution region, plug it into both inequalities. If it satisfies both, it's in the feasible region!

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Math Problem Analysis

Mathematical Concepts

Systems of Linear Inequalities
Graphing Linear Equations
Algebra

Formulas

4x - y = 1
x + 2y = 7

Theorems

Linear inequality system solution
Intersection of lines

Suitable Grade Level

Grades 9-11