Question

The manager of a furniture factory finds that it costs $2400 to manufacture 90 chairs in one day and $4800 to produce 290 chairs in one day.
(a) Express the cost C (in dollars) as a function of the number of chairs x produced, assuming that it is linear.

Answer 1

(90,2400)(290,4800)
slope = (4800 - 2400) / (290 - 90)
slope = 2400/200 = 12

y = mx + b
slope(m) = 12
(90,2400)...x = 90 and y = 2400
now we sub...we r looking for b, the y int
2400 = 12(90) + b
2400 = 1080 + b
2400 - 1080 = b
1320 = b

equation is : y = 12x + 1320
function = C(x) = 12x + 1320 <===