Hey there! I'm happy to help!
Here's how to find the distance between any two points.
Subtract the x values.
5-(-1)=5+1=6
Square that.
6²=36
Subtract the y values.
0-4=-4
Square that.
-4²=16
Add the two numbers you got.
36+16=52
And square root it.
√52≈7.2.
Have a wonderful day! :D