 Hello and welcome to the session. I am Aasha and I am going to help you with the following question that says the length L of a copper rod is a linear function of its Celsius temperature C in an experiment if L is equal to 124.942 when C is 20 and L is equal to 125.134 when C is equal to 110 express L in terms of C. Let us now begin with the solution and they are given that L is a linear function of its Celsius temperature therefore L is equal to AC plus B since any linear function is of the form AX plus B is equal to 0 this is a general form of linear equation and here we are given that L is a linear function of its Celsius temperature therefore L is equal to AC plus B. Now the first case is L is equal to 124.942 when C is equal to 20 so this equation can be further written as 124.942 is equal to A into 20 plus B so this is equation number one. Second we are given that L is equal to 125.134 when C is equal to 110 therefore we have 125.134 is equal to A into 110 plus B so this is equation number two. Now subtracting one from two we have 125.134 is equal to 110 into A plus B and 124 plus 942 is equal to 20 into A plus B. Now solving it B cancels up with minus B 110 A minus 20 A is 98 and subtracting 124.942 from 125.134 we get 0.192 so this implies A is equal to 0.192 upon 90 let this be equation number three. Now as we know L is equal to AC plus B therefore this implies that B is equal to L minus AC and now substituting the value of B in equation number one which is 124.942 is equal to 20 times of A plus B and B is L minus AC therefore this implies that L is equal to 124.942 plus C minus 20. Now substituting the value of A so we have L is equal to 124.942 plus 0.192 upon 90 into C minus 20 therefore L can be expressed in the terms of C as 0.192 upon 90 into C minus 20 plus 124.942 this is the answer hope you have understood it take care and have a good day.