How many bracelets can she make in 3.5 hours

Look at the graph.
If you go to x = 2, you see y = 6.
x is the independent variable and represents the number of hours she works.
Now go up from x = 2 on the x-axis until you reach the line. At that point, y = 6. y is the dependent variable and shows how many bracelets she makes.
She makes 6 bracelets in 2 hours.
If you divide the number of bracelets by the number of hours, you get the unit rate of bracelets per hour.

6 bracelets / 2 hours = 3 bracelets/hour

Now multiply the unit rate by 3.5 hours

3 bracelets / hour * 3.5 hours = 10.5 bracelets.

In 3.5 hours, she makes 10.5 bracelets.