Rates like $ per channel is a slope, "m". The added fee is a constant so it's the intercept "b". y = mx + b
So for the first problem (9) (a) y = total cost in dollars x = number of premium channels y = 16x + 44 (b) when x = 3 channels y = 16(3) + 44 y = 92 $
the second problem (10) (a) every 4 years the tree grows by 12-9=3 ft So the unit rate or slope will be 3 ft per 4 yrs, (3/4). You can see this also by solving for slope "m" using the given points (4,9) and (8,12).
x = number of years y = height of tree in ft y = (3/4)x + b use one of the points to find the y-intercept "b".
9 = (3/4)(4) + b 9 = 3 + b 9 - 3 = b 6 = b y = (3/4)x + 6
(b) when x = 16 y = (3/4)(16) + 6 y = 12 + 6 y = 18 ft
