A photo lab manager graphed the cost of having photos developed as a function of the number of photos in the order. The graph is a line with a slope of 1/10 that passes through (10,6). Write an equation in slope-intercept form that describes the cost to have photos developed. How much does it cost to have 25 photos developed?

Answer 1

I will assume that your given ordered pair (10,6) is of the type (number , cost), then

cost - 6 = (1/10)(number -10)
cost = (1/10) number -1 + 6

cost = (1/10)n + 5

so if n = 25
cost = (1/10)(25) + 5 = 7.5 units of cost (you gave no units)

Answer 2

So if slope intercept form is y=mx+b what would this equation look like for this word problem?

Thanks

Answer 3

I gave it to you ...
instead of y I have "cost"
instead of x I have "n"

y = mx + b <-----> cost = (1/10)n + 5

Answer 4

It should be y=10x+5
it would cost $7.50