Sangeetha Pulapaka
1

Step 1: Recall  the standard form of a linear equation in two variables

             A standard form of a  linear equation in two variables is in the form ax+by = c

Step 1: Assume one piece of cable to be x and the other piece of cable to be y

Step 2: Write the first linear equation as x+ y = 84

Step 3:  Assume x to be 18 metres longer than y

Step 4: Write the second linear equation as x = 18 +y

Step 5:  Use the substitution (easy) method, write both the equations in x = form or y = form

              x = 84 -y

              x = 18 +y

Step 6: Write them across each other

            84 - y = 18 +y

Step 7: Solve for y

        84 - y = 18 + y

        2y = 102

          y = 51

Step 7: Substitute the value of y in any one of the equations to find the value of x

          x = 84 - 51 = 33

        So the length of one piece of cable is 33 m and the length of the other piece of cable is 51m