Find the straight line passing through points A (2; -1; 3) and B (2; 3; 3) and write down its equation.

We have points A (2; -1; 3) and B (2; 3; 3).

The equation of a straight line passing through two points with coordinates (x1; y1; z1) and (x2; y2; z2) has the following form:

(x – x1) / (x2 – x1) = (y – y1) / (y2 – y1) = (z – z1) / (z2 – z1);

Let’s substitute the coordinates of our points:

(x – 2) / (2 – 2) = (y + 1) / (3 + 1) = (z – 3) / (3 – 3);

(x – 2) / 0 = (y + 1) / 4 = (z – 3) / 0.