Question

Pens cost $1.50 each at a school store. Graph a line that represents y, the cost,in dollars, of purchasing x pens at the store.To graph a line, select two points on the coordinate plane. A line will be drawnthrough the points.

Answer 1

If x is the number of pens to buy, and each pen costs $1.50, then, the realtion in between the total cost of x pens, given by y, is:

y = 1.50x

to graph a line which represents the previous function, calculate y for two values of x, for instance, x = 2 and x = 6:

y = 1.50(2) = 3.00

y = 1.50(6) = 9.00

then, you obtain the following points:

(2 ,3.00)

(6, 9.00)

the graph is:

the blue and red points are the calculated points.