Helen rented a kayak at the lake. There is a charge of $10 as an initial fee and then $2 an hour for every hour that she uses the kayak. If the total charge is $22 , how many hours did she kayak?

Where m is the slope of the line and b is the y-intercept of the line, or the y-coordinate of the point at which the line crosses the y-axis. to write an equation in slope-intercept form, given a graph of that equation, pick two points on the line and use them to find the slope. this is the value of m in the equation.