I need help with interpreting a linear equation

Question

A one year old bluegill fish is 3 inches long, while a four year old bluegill fish is 6.6 inches long. Assuming growth rate can be approximated by a linear equation, Write an equation in slope-intercept form for the length of a bluegill fish in inches after t years.

Answer 1

f(x) = Mx + b where M is the slope and b is the intercept of the linear function.

 

f(1) = 3

f(4) = 6.6

 

the slope is (6.6 - 3)/(4-1) = 3.6/3 = 1.2

So the growth rate is 1.2 inches per year.

 

The intercept is B = y - mx = 3 - (1.2)1 = 3 - 1.2 = 1.8

 

The linear function is f(t) =1.2t + 1.8 where t is in years