Question
Thu September 22, 2011 By:

In the episode of linear equation in two variables it was taught that b is not equal to 0 but in the question 7x=-5,it was given b=0.Please explain it.

Expert Reply
Mon September 26, 2011

Any equation which can be put in the form ax + by + c = 0, where a, b and c are real numbers, and a and b are not both zero, is called a linear equation in two variables.

 

In the example (considered in the episode), 7x = -5, we are just writing this linear equation (in one variable) in the form of linear equation in two variables.

We can conveniently convert this into the required form by adding 0y to the given equation as adding 0y to the equation does not change it in any manner as 0y = = 0. Hence, the given equation can be written as 7x + 0y = –5.

 

Thus, all linear equations of one variable can be converted into linear equations in two variables.

In short, it can be said that the equation ax + by + c = 0, where a, b and c are real numbers, and a and b are not both zero is the general form of the linear equation in two variables and 7x + 0y = –5 is a particular case in which we have written a linear equation in one variable in the form of linear equation in two variables.

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