Question

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

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