Question

A vine maple grows fast when it is planted under the cover of cedar trees. One month after it is planted it has grown 12 inches, and after eight weeks it had grown 19 inches. Write an equation that models the growth, in inches, of the vine maple as a function of time, in weeks.

Answer 1

y = (7/4)(x -4) +12

Explanation:

The rate of growth is ...

(19 in -12 in)/(8 wk -4 wk) = 7/4 in/wk

Using this slope in a point-slope form of the equation for a line, we get ...

y = m(x -h) +k . . . . . line with slope m through point (h, k)

y = (7/4)(x -4) +12 . . . . . line with slope 7/4 through the point (4 wk, 12 in)