 Hello and welcome to the session. In this session we shall study the concept of variables. We can easily understand this by an example. Let's take an example. Jenny wants to prepare a dried fruit mixture in which she wants to put dried mangoes, dried pineapples and dried apples. She can put any amount of fruit into the mixture as she likes. So here she can change the values of the amount of fruits added to the mixture. Therefore we can say that the amount of fruit is variable due to which the amount of dried fruit mixture is also a variable. So we can say a variable is a value that may change within the scope of a given problem. A variable can be used to represent a quantity that can change often in a relationship to another changing quantity. Variables can be represented by small alphabets like small a, small b, small c or small x, small y or small z and so on. In the above example the amount of dried fruit mixture depends on the amount of fruits added. So amount of dried mangoes, dried pineapples and dried apples are independent variables and the amount of dried fruit mixture prepared is the dependent variable. And we have seen that variables help in broadening the relationship between two quantities with the help of dependent and independent variables. So we can say in our system independent variables are taken as inputs which can be given specific values freely and dependent variables are the variables that are dependent by other variables in the expression if their values depend on the values of the independent variables Any year old problem if we represent quantities as variables we can describe our relationship between the quantities by forming an equation. Now in the previous example suppose the amount of dried mangoes be in the amount of dried pineapples be p and the amount of dried apples is a here m, p and a are independent variables let the amount of mixture prepared be x then x is the dependent variable and we know that this dried fruit mixture is prepared by adding dried mangoes, dried pineapples and dried apples. So we have x which denotes the amount of mixture is equal to n that is the amount of dried mangoes plus p the amount of dried pineapples plus a the amount of dried apples which is the required linear equation by giving any values to m, p and a we can find the value of x. Suppose m is equal to 2 pounds p is equal to 4 pounds and a is equal to 3 pounds then x which is given by m plus p plus a will be equal to 2 plus 4 plus 3 that is 9 pounds. So if 2 pounds of dried mangoes 4 pounds of dried pineapples and 3 pounds of dried apples are added to make a fruit mixture then 9 pounds of mixture is prepared. Thus variables can be used to form linear equations in one or more variables this completes our session hope you enjoyed this session.