Help with my Algebra 2 homework

I need help with this Algebra 2 problem for my homework. I do not remember going over this in class so please help!

In 1950 the life expectancy of women was 72 years. In 1970 it was 75 years. Let E represent the life expectancy and t the number of years since 1950 (t=0 gives 1950 and t=10 gives 1960).
a. Fit a linear function to the data points. [they are (0,72) and (20,75).]
b.Use the function to predict the life expectancy of women in 2003; in 2018.

A.
set the function as E=kt+b
put these two points in E=kt+b, then we can get b=72 and 20k+b=75
then put b=72 into 20k+b=75 and get k=3/20
so the linear function is E=3/20 t+72

B.
on this question,we have already known that t=0 which is in 1950, t=10 is in 1960.
therefore, t=53 is in 2003.
then we put t=53 into E=3/20 t+72,we get answer is 79.95,which is 80 years.
t=68 is in 2018,so we put t=68 into linear function,we get answer is 82.2,which is 82 years.


I hope it will help u.

It says linear function, so just use

y2-y1/ x2-x1

75-72/ 20-0

That gives you a function with a slope y=.15x+72

x is the number of years since 1950.

Use it to figure out the life expectancy for 2003 and 2018.