Answer:
a. C(F) = (5/9).F - (160/9)
b. They both readings are equal at C = F = - 40
Explanation:
They are telling us that we are looking for a linear function
If C(F) = a.F + b is the linear function, we use the data to find a and b
C(32) = a.32 + b
0 = a.32 + b
b = - (a.32) (1)
And then
C(212) = a.212 + b
100 = a.212 + b (2)
replacing (1) in (2) we obtain
100 = a.212 + [-(a.32)]
100 = a.212 - a.32
100 = 180.a
a = 100/180
a = 5/9
If a = 5/9 then b = -(a.32)
b = - (5/9).32
b = - (160/9) and the linear function is
C(F) = (5/9).F - (160/9)
For b. they are asking us for a X reading. We must equalize C and F
X = (5/9).X - (160/9)
(4/9).X = - (160/9)
X = -40
C = F at temperature X = - 40