Math Problem Statement

Which graph correctly shows the system of equations { x - 2y = -7 , -4x + y = 14 }?

Solution

Let's work through this system of equations to identify the correct graph:

The given system of equations is:

  1. x2y=7x - 2y = -7
  2. 4x+y=14-4x + y = 14

We will start by solving both equations for yy, and then we can identify the graph that corresponds to the solution.

Solving the first equation x2y=7x - 2y = -7:

Rearrange for yy: x2y=7=>2y=x7=>y=x+72x - 2y = -7 \quad \text{=>} \quad -2y = -x - 7 \quad \text{=>} \quad y = \frac{x + 7}{2} So, the first equation in slope-intercept form is: y=12x+72y = \frac{1}{2}x + \frac{7}{2}

Solving the second equation 4x+y=14-4x + y = 14:

Rearrange for yy: 4x+y=14=>y=4x+14-4x + y = 14 \quad \text{=>} \quad y = 4x + 14 So, the second equation in slope-intercept form is: y=4x+14y = 4x + 14

Now that we have the equations in slope-intercept form:

  1. y=12x+72y = \frac{1}{2}x + \frac{7}{2}
  2. y=4x+14y = 4x + 14

The slopes of the lines are 12\frac{1}{2} and 44, respectively, and their y-intercepts are 72\frac{7}{2} and 1414.

Graph Analysis:

  • The first graph shows two lines with distinct slopes, and it seems to intersect at a point. This graph is most likely the correct one, based on the equations.

  • The second and third graphs are showing either mismatched slopes or intercepts.

Conclusion:

Based on the slopes and y-intercepts, the third graph most closely represents the system of equations.

Let me know if you need further clarification or have any other questions!


Here are 5 related questions:

  1. How do you determine the slope and y-intercept from an equation?
  2. What is the meaning of the point where two lines intersect in a system of equations?
  3. How do you solve a system of linear equations using substitution or elimination?
  4. What is the significance of a system with parallel lines?
  5. How do you find the point of intersection for two lines algebraically?

Tip: When graphing a system of equations, always check the slope and y-intercept for each equation to ensure the graph is correct.

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Equations
Graphing Linear Equations

Formulas

y = (x + 7) / 2
y = 4x + 14

Theorems

Slope-intercept form of a linear equation

Suitable Grade Level

Grades 7-9