We have already discussed about the various methods of solving linear equations in two variables. Let us discuss with graphing systems of linear equations in two variables. We shall also discuss solving systems of linear equations by graphing. By learning the method of linear equations online you will be able to understand the types of solutions.

Since the domain consists of all real numbers, we plug in values for x and find the corresponding values of y.

To graph the linear equation, we find the x and y intercepts by plugging in y = 0 and x = 0 respectively.

Let us discuss the following example.

4x - 3y = 12; x + y = 3

4x - 3y = 12

x |
y |

0 | -4 |

3 | 0 |

x+ y = 4

x |
y |

0 | 3 |

3 |
0 |

By graphing linear equations the solution to the linear equations will be as follows.

1. If the graph of the pair of linear equations are of intersecting lines then the system of linear equations in two variables is consistent and have unique solution ( one and only one solution)

2. If the graph of the pair of linear equations are of parallel lines then the system of linear equations in two variables is inconsistent and have no solution.

3. If the graph of the pair of linear equations are of coinciding lines then the system of linear equations in two variables is consistent and have infinite number of solutions.

Let us study the following system of equations and their respective graphs.

x - 2y = 1

x |
y |

0 |
1 |

-0.5 | 0 |

x + y = 4

Let us find the x and y intercepts and record it in the tables given below.

x |
y |

0 |
4 |

4 |
0 |

By plotting the points we see that the system of equations

Hence the solution is (3,1)

3x - 2y = 6

x |
y |

0 |
-3 |

2 |
0 |

6x - 4y = -12

x |
y |

0 |
3 |

-2 | 0 |

From the graph we observe that the lines are

5 x + 2y = 10

x |
y |

0 |
5 |

2 | 0 |

10 x + 4y = 20

x |
y |

-2 | 10 |

4 |
- 5 |

By plotting the above points and graphing we observe that the pair of lines

This shows that the system of given equation has infinite number of solutions.

we got the solution to the pair of equations as (3, 1), as the two lines intersect at this point.

When we graph the linear inequalities, we shade the region satisfying the given inequality.

Let us consider, x - 2y > = 1 and x + y < = 4.

We observe that we get a region between the two common shaded region .This common region is the solution to the inequalities.

Any point in this region will satisfy the given inequality.

1. x + y = 3 ; 3x + 5y = 15.

2. 3x - y = 2, 9x - 3y = 6

3. 4x - 5y = 4 and 8x - 10 y = 40

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