Determine k and m knowing that the line y = kx + m passes through the points: A (-1; 3); B (1; 7)

To solve, we substitute the coordinates of points A and B into the equation, and solve for m and n. A (-1; 3), B (1; 7).

Substitute the coordinates of point A, then – point B:

y = k * x + m; 3 = k * (-1) + m; -k + m = 3;

Substitute in the equation of the straight line coordinates of point B: 7 = k + m, add the equations, we get:

2 * m = 10; m = 5; k = 7 – m = 7 – 5 = 2; k = 2.

Thus, the equation of the straight line looks like this: y = 2 * x + 5.

To check, we substitute the coordinates of points A and B:

3 = -1 * 2 + 5; 3 = 3; 7 = 2 * (1) + 5 = 7. Solved right.