Question

After birth, a baby's weight increased at a steady rate for several weeks.

A linear model of this situation contains the values (1, 7.2) and (6, 9.2), where x represents the number of weeks, and y represents the baby's weight, in pounds.
What was the baby's weight at birth?

A.0.4 of a pound

B.5 pounds

C.7.2 pounds

D.6.8 pounds

Answer 1

y=mx+b first we will find m or the slope.

m=(9.2-7.2)/(6-1)=2/5=0.4 now we have:

y=0.4x+b, using either point we can now solve for b, the "y-intercept", which in this case is the weight at birth :) I'll use point (1, 7.2) so our equation is:

7.2=0.4+b, b=6.8

y=0.4x+6.8

So the weight at birth was 6.8 lb