@hayhay12345 Sorry, I wasn't online. The answer to the first question is august ; You have to use the least squares method in order to determine the equations for revenue and expense. Alternatively draw a graph for the values of both revenue and expense (separately!) and draw a line between the points so that you end up with a graph that fits the data. The equation for revenue will be: 4100m + 300 (where m = month) The equation for expense will be: 1900m + 19900 if revenue and expense are to be equal, their equations have to be dependent. therefore subtracting the two equations, you get: 2200m - 19600 m = 19600/2200 = 8.9 August is the 8th month, therefore revenue and expense will be equal at the end of august. Your second answer is correct.