You already know that calculating the coordinates of the graph of a linear function is an important aspect of mathematics, which helps understand and model various real-life situations. Understanding linear functions can help better understand how various factors affect total costs. But now imagine that you want to learn to skate and your parents face a dilemma - to buy skates or to rent them every time you go skating. Suitable skates for beginners cost 90 euros, but skate rental costs 3 euros per hour, and in both cases, it costs 6 euros per hour-long skating session. To repeat - A linear function is a mathematical relationship that can be expressed as y=mx+b. In the situation being considered, y is the dependent variable (total costs), m is the variable costs, x is the independent variable (number of visits), and b is the fixed costs. It is important to remember that b is also the graph's intersection point with the y-axis. In this example: b is 90 euros for the purchase of skates. M is the payment for entering the ice rink and also for skate rental, if necessary, x is the number of visits to the ice rink, and y is the total costs. The linear function in the situation with skate purchase looks like this: y equals six x plus ninety, whereas in the situation where skates are rented: y equals nine x plus zero - nine because, in addition to the charge for ice usage, skates must also be rented, but zero can also not be written, however, for clarity and as a reminder of the absence of fixed expenses and as the graph's intersection point with the y-axis - let it remain! To draw both linear function graphs, we need at least two-point coordinates through which to draw a line, this is a story about calculating the points of the linear function graph. The first point's coordinates are already known to us because they are the fixed expenses which, by the way, are also the intersection points with the y-axis, in the first case they are zero and ninety, in the second case zero and zero, but for calculating the coordinates of the second point we will take the x value twenty - in the first case, and the x value ten - for the second function. In the first case, six times twenty plus ninety is two hundred ten (20, 210) but in the second case, nine times ten plus zero is ninety (10, 90). Now we mark the points. We draw straight lines through them. and here it is visually clear under what conditions the purchase of skates becomes economically viable. Of course, in these examples, there can be many other considerations as to why to buy something or not, but Such examples help understand mathematical concepts in a practical context. It is a mistake to think that mathematics is purely theoretical knowledge, mathematics is practical - very much so!