75 something 12 km north is where he at
a)
Let t represents number of years after 1900
so that means for 1900, value of t is 0
We are given point as (0,55)
and it says that life expectancy increases by 0.2
so that means slope,m=0.2
equation of line is y=mt +b
or y=0.2t +b
now we use point (0,55)
55 =0.2(0) +b
55 =0+b
55= b
so b=55
plug it back into the equation,we get
y=0.2t +55
b)
We are given y=73
so we plug it into the equation we got in part a and solve for t
y=0.2t +55
73 =0.2t +55
73-55 =0.2t
18 =0.2t
18/0.2 =t
90 =t
so t=90
This means the birth year =1900+t =1900+90 =1990
Answers 3 and 4! since there is a negative power, that’s the only time the 0’s are added to the front :)
