Atypical american baby weighs about 8 pounds at birth and gains about 1.5 pounds per month for the first year of life. what equation relates weigh in pounds to age a
in months

Let's start by defining our variables:

W = weight

M = months since birth

We know that the baby weights about 8 pounds at birth, so this is our starting value

W = 8

We also know that every month this increases by 1.5 pounds every month since birth.

W = 8 + 1.5M

So our equation that relates weigh in pounds to age in months is

W = 1.5M + 8