The formula for calculating the distance between two points is:
#d = sqrt((color(red)(x_2) - color(blue)(x_1))^2 + (color(red)(y_2) - color(blue)(y_1))^2 + (color(red)(z_2) - color(blue)(z_1))^2)#
Substituting the values from the points in the problem gives:
#d = sqrt((color(red)(-5) - color(blue)(-1))^2 + (color(red)(-1) - color(blue)(1))^2 + (color(red)(1) - color(blue)(3))^2)#
#d = sqrt((color(red)(-5) + color(blue)(1))^2 + (color(red)(-1) - color(blue)(1))^2 + (color(red)(1) - color(blue)(3))^2)#
#d = sqrt((-4)^2 + (-2)^2 + (-2)^2)#
#d = sqrt(16 + 4 + 4)#
#d = sqrt(24)#
#d = sqrt(4 * 6)#
#d = sqrt(4)sqrt(6)#
#d = 2sqrt(6)#
Or, if you require a non-radical answer:
#d = 4.899# rounded to the nearest thousandth