To find the point(s) where x1 and x2 are equal, we can set the two equations equal to each other:

10 + 15t = 100 - 25t

Solving for t, we get:

40t = 90

t = 90/40

t = 9/4 = 2.25

To find the values of x1 and x2 at t = 2.25:

x1 = 10 + 15(2.25) = 45.5
x2 = 100 - 25(2.25) = 36.25

Therefore, when t = 2.25, x1 = 45.5 and x2 = 36.25.