Answer:
144 people were originally at the party.
Step-by-step explanation:
18 boys is one fifth of the second boys population, so the second population is 18x9 = 162. The original population would be 162-18, which equals 144.
The equation of a line starting from two points is:
From the first point you get: x1 = -1, y1 = -2
From the second point you get: x2 = 3, y2 = 10
Replace x1, y1, x2, y2 in the equation of the line and you get:
From this you get the equation of your line: