Answer:
To find the value of x for which the distance between the points P(4, -5) and Q(12, x) is 10 units, we can use the distance formula.
The distance formula is given by:

Here, P(4, -5) is our first point with coordinates (x1, y1) and Q(12, x) is our second point with coordinates (x2, y2).
Let's substitute the coordinates into the distance formula:

Simplifying the equation:

Squaring both sides of the equation:


Subtracting 64 from both sides of the equation:

Taking the square root of both sides:
6 = x + 5 or -6 = x + 5
Solving for x, we get two possible values:

Therefore, the values of x for which the distance between the points P(4, -5) and Q(12, x) is 10 units are x = 1 and x = -11.