Question

A girls walks 12m northwards 5m eastwards and 7m southwards her total displacement is?

Answer 1

North = 12-7 = 5
East = 5
sqrt(25+25) = 25 sqrt 2 m
(but I assume you really meant mi, miles not meters)
45 degrees east of north

Answer 2

Using pythagora's method D=N-S=E D=12-7=5 5×5=25 square root of 25=5 so the total displacement is =5