Answer 1

It is given that distance between P (4, p) and Q(1, 0)  is 5.

In general, the distance between A(x₁,y₁)  and B(x₂ , y₂) is given by,

`AB^2 = (x_2-x_1)^2 + (y_2-y_1)^2`

So,

`5^2 = (4-1)^2+(p-0)^2`

On further simplification,

`p^2 = 16`

   `p = +-4`

So,

   `p = +-4`