Linear proportionality graph passes through point C (-1; 4) Define this function by the formula.

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.