Question 61·Easy·Linear Equations in Two Variables
The graph shows the possible combinations of the number of sketchbooks, , and the number of markers, , that could be purchased for $24 at a certain store.
If Dana purchased sketchbooks and spent a total of $24 on sketchbooks and markers, how many markers did Dana purchase?
For a graph of a linear relationship, treat the line as a set of solution pairs . When you are given one coordinate (like ), go to that value on the axis, find where it meets the line, and read the other coordinate () directly from the graph.
Hints
What the line represents
Every point on the line is a combination of sketchbooks and markers that totals $24.
Use the given -value
Since Dana bought sketchbooks, find the point on the line where the -coordinate is 7.
Read the output
Once you find the point above on the line, read its -coordinate from the vertical axis.
Desmos Guide
Graph the line
In Desmos, enter the line (this matches a line passing through and ).
Evaluate at
Create the point (or use a table) to see the corresponding -value on the line.
State the result
The corresponding value is , so Dana purchased 10 markers.
Step-by-step Explanation
Locate on the graph
Find on the horizontal axis and move vertically until you reach the line.
Read the corresponding -value
Read the -coordinate of that point on the line. The graph shows , so Dana purchased 10 markers.