 In this video, we provide the solution to question number three for the practice exam number one for math 1060 And we're asked to find the distance between the points 2 comma 5 and 4 comma negative 1 So we just want to apply the distance formula which is derived from the Pythagorean equation The distance between these is going to be the square root. Well, let's just write the formula first of all It's going to be the square root of x1 minus x2 squared plus Y1 minus y2 squared all inside of the square root and be aware the square root does not cancel out with these squares Otherwise that would be the distance formula we use Using the specific numbers here. We're going to get 2 minus 4 squared plus 5 minus a negative 1 square. That's a double negative. So it's actually going to be a positive You're going to get 5 plus 1 And then of course we have 2 minus 4 All inside the square root 2 minus 4 is going to give us a negative 2 squared 5 plus 1 is a 6 So we get 6 squared Don't be too worried about the negative sign there because when you square negative it's going to become positive anyways So you're going to get 4 plus 36 all inside of the square root This adds together to be the square root of 40 if you search among the answers You don't see the square root of 40 Probably what happens is they're going to expect you to simplify the square root there 40 Of course factors as 4 times 10 for being a perfect square So this is the square root of 4 times the square root of 10 the square root of 4 is 2 So we get the distance is 2 times the square root of 10 So we see that the correct answer is choice D