Here is the function graphed. This is what you asked for.
0.4kg per week. so 0.4kg x 6 weeks is 2.4kgs
Answer:

Step-by-step explanation:
Assuming we want to find the equation (74,2) and (4,9)
This is an equation of a straight.
Let this equation be y=mx+b.

We substitute the slope and (4,9) to get:

We rewrite in standard form to get:
