For children between ages 4 and 18, height y (in inches) is frequently a linear function of age t (in years). The height of a certain child is 41 inches at age 4 and 44 inches at age 5.

height = 3*age + 29

Step-by-step explanation:

Let linear equation be

height = m*age + c [m and c are independent constants]

given

41 inches age 4

44 inches age 5

put these data in above linear equation

then,

41 = m*4 + c ... (1)

44 = m*5 + c ... (2)

subtract (2) from (1)

3 = m

c = 29

So, equation is

height = 3*age + 29 (for all age group between 4 and 18)