Question

the weight of a puppy was monitored for the first year of its life. the weight, in grams, of the puppy has a strong linear relationship with the number, x, since birth. the relationship can be modeled by the function r(x) = 1,200x + 400. what is the meaning of the y-intercept of the function?
a the puppy weighed about 400 grams at birth.
b the puppy weighed about 1,200 grams at birth.
c the weight of the puppy increases by about 400 grams per month.
d the weight of the puppy increases by about 1,200 grams per month.

Explanation:

Step1: Identify linear function form

The function is $f(x) = mx + b$, where $b$ is the y-intercept.

Step2: Find y-intercept value

Here, $f(x) = 1200x + 400$, so $b = 400$. The y-intercept occurs at $x=0$ (number of months since birth), meaning the puppy's weight at birth is 400 grams.

Answer:

A. The puppy weighed about 400 grams at birth.