Question

The distance between points (5,9) and (-7,-7)

Answer 1

You need to find the change in x and y 

change in x = 12 
change in y = 16 

to find the distance you use a^2+ b^2 = c^2
or in this case x^2 + y^2 = d^2

144+256 = 400 

$\sqrt{400}$

=20 
so distance equals 20


I hope this helps!