Use the distance formula.
The distance, d, between points [tex] (x_1, y_1) [/tex]
and [tex] (x_2, y_2) [/tex] is given by the distance formula below.
[tex] d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} [/tex]
Now we can apply the formula to your points.
Let Point 1 be (2, 3) and Point 2 be (5, -4).
Then you have
[tex] x_1 = 2~~~~y_1 = 3~~~~x_2 = 5~~~~y_2 = -4 [/tex]
[tex] d = \sqrt{(5 - 2)^2 + (-4 - 3)^2} [/tex]
[tex] d = \sqrt{(3)^2 + (-7)^2} [/tex]
[tex] d = \sqrt{9 + 49} [/tex]
[tex] d = \sqrt{58} [/tex]
Answer: the distance is sqrt(58)