HELP ME PLEASEEE!!! I DONT UNDERSTAND THIS ONE

News cameras take an overhead picture of a crowd at an outdoor event journalist then count the total number of people in the picture and use the sample of estimate the total number of people in the crowd this process is an example of

Write two subtraction equations that are equivalent to 5 + 12 = 17.

What is the area of a triangle with vertices at (-3 3) (-3,2) and (1,2)?