Type 3 in the Forward box. Double click on the equation and ctrl c to copy click on the cell and ctrl v to paste. A few pointers about the FORECASTLINEAR Function.
The TREND formula in excel will be.
INTERCEPTyx Assuming the x range is B2B13 and the y range is C2C13 the real-life formulas go as follows. On the Number tab click Number in the Category list and then change the Decimal placessetting to 30 or less. Type TREND or use the Insert Function fx menu in Excel. Well add 1 to the value returned by MATCH to get 60 for x1 and 1067 for y.