Math Problem Statement

Distinguish the number of solutions. Show your work and explain how you know the number of solutions. -2x + y = 1 y = -2x + 4

Solution

To determine the number of solutions for the given system of equations:

Given equations:

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

Step 1: Recognize the equations

Notice that both equations are in the form of a linear equation. We can examine the slopes and y-intercepts to determine if they are parallel, coincident, or intersecting.

Step 2: Compare slopes

Rewrite the first equation to clearly identify its slope and y-intercept.

  1. Equation 1: 2x+y=1-2x + y = 1 Rearrange to solve for yy: y=2x+1y = 2x + 1

    Now, the first equation becomes: y=2x+1y = 2x + 1 The slope is 22, and the y-intercept is 11.

  2. Equation 2: (already in slope-intercept form) y=2x+4y = -2x + 4 The slope here is 2-2, and the y-intercept is 44.

Step 3: Determine if they are parallel, coincident, or intersecting

  • If two lines have the same slope but different y-intercepts, they are parallel and have no solutions (no intersection points).
  • If two lines have the same slope and the same y-intercept, they are coincident and have infinitely many solutions (all points on one line are also on the other).
  • If two lines have different slopes, they intersect at exactly one point (a unique solution).

Step 4: Analyze the slopes and y-intercepts

  • The slope of the first equation (y=2x+1y = 2x + 1) is 22.
  • The slope of the second equation (y=2x+4y = -2x + 4) is 2-2.

Since the slopes are different (22 and 2-2), the lines are not parallel. Therefore, these lines will intersect at exactly one point, meaning there is one unique solution to this system of equations.

Conclusion:

The system of equations has exactly one solution.

Summary:

  1. Compare slopes and y-intercepts.
  2. Different slopes indicate one solution (an intersection point).
  3. Same slope with different y-intercepts indicates no solution.
  4. Same slope and y-intercept indicate infinitely many solutions.

Would you like further details on solving for the exact intersection point or have any questions?


Here are five related questions that could expand on this topic:

  1. How can we find the exact intersection point for these two lines?
  2. What is the graphical interpretation of a system with no solutions?
  3. How can we use substitution or elimination to solve a system of equations?
  4. How does changing the slope affect the number of solutions in a system?
  5. Can systems of nonlinear equations have similar classifications for solutions?

Tip: When comparing two linear equations, always start by analyzing their slopes to quickly assess the number of possible solutions.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
System of Equations

Formulas

Slope-intercept form y = mx + b

Theorems

Conditions for the number of solutions in a system of linear equations

Suitable Grade Level

Grades 8-10