The graph we are going to build is a straight line. Because the graph of direct proportionality has the form of a straight line equation:
y = kx, where k is the proportionality coefficient, if k> 0, then the function increases, and vice versa.
Thus, the first point through which the straight line will pass has coordinates (0,0), based on the equation above, the second point is given by condition. Let’s find the coefficient k from the coordinates of the second point:
4 = k * (-1);
k = -4.
Answer: the formula of direct proportionality y = -4 * x.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.