Find the point at which the straight line passing through the points A (5; 5) and B (1; 3) intersects the Ox axis.

If the straight line passes through the points, we substitute their coordinates into the equation of the straight line y = kx + b and obtain a system of equations from which we can find k, b and write down the equation of the straight line.

5 = 5k + b,

3 = k + b.

From the second equation we express k = 3 – b, substitute the obtained expression instead of k into the first equation:

5 = 5 * (3 – b) + b

5 = 15 – 5b + b

4b = 10

b = 2.5.

k = 3 – 2.5 = 0.5.

Equation of a straight line: y = 0.5x + 2.5.

The intersection with the abscissa means that y = 0.

0 = 0.5x + 2.5

0.5x = -2.5

x = -5.

Answer: intersection point (-5; 0).