Question

NEXTEQuestion 4/5For $1200, a business can post an advertisement for 30 days. For $1500, theadvertisement will be posted for 60 days. The relationship comparing cost to daysis linear. Which function can be used to model the relationship between cost, y,and the number of days, x, that an advertisement will be posted?A y = 300x + 1200y = 1200x + 300y = 10x + 900D y = 900x + 10

Answer 1

y: cost

x: number of days

the following points are on the line (30, 1200) and (60, 1500)

The slope of a line given two points (x1, y1) and (x2, y2) is computed as follows:

`m=(y_2-y_1)/(x_2-x_1)`

Replacing with (30, 1200) and (60, 1500), we get:

`m=(1500-1200)/(60-30)=(300)/(30)=10`

The slope-intercept form of a line is:

y = mx + b

where m is the slope and b the y-intercept.

Replacing with point (30, 1200) and m = 10, we get:

1200 = 10(30) + b

1200 = 300 + b

1200 - 300 = b

900 = b

Then, the equation is:

y = 10x + 900