Story problem
"According to the US Bureau of the Census, the world population in the year 1950 was A=2555360972, and in 2000 it was B=6079006982 We'll use A and B so we don't have to keep writing those large and idiosyncratic numbers. We usually use y and x in the equation of a line, but in this and the following problem let's use N and t instead. t stands for time and N for the size of the population.
If N(t)=mt+b
such that N(1950)=A and N(2000)=B, then m=[blank]and b=[blank]
Suppose you want to estimate the population in 1975. To that end you compute N(1975) =[blank]

Question

Story problem
"According to the US Bureau of the Census, the world population in the year 1950 was A=2555360972, and in 2000 it was B=6079006982 We'll use A and B so we don't have to keep writing those large and idiosyncratic numbers. We usually use y and x in the equation of a line, but in this and the following problem let's use N and t instead. t stands for time and N for the size of the population. 
If N(t)=mt+b
such that N(1950)=A and N(2000)=B, then m=[blank]and b=[blank]
Suppose you want to estimate the population in 1975. To that end you compute N(1975) =[blank]

campbell_st · Answer

ok... so you need to find the slope given 2 ordered pairs

A(1950, 2555360972) and B(2000, 607900982)

the years are the independents  so in the denominator, population is dependent and so in the numerator 

 Once you find the slope, substitute either ordered pair into 

N(t) = mt + b

and evaluate to find b

campbell_st · Answer

so once you get the equation, substitute t = 1975 to get an estimate of the population.