First find the slope m. slope formula: [tex]\frac{y_{2} - y_{1} }{x_{2} - x_{1} }[/tex]
Let's use (0, -20) for x1 and y1; and (2, 10) for x2 and y2
[tex]\frac{10-(-20)}{2-0}[/tex] = [tex]\frac{30}{2}[/tex] = [tex]15[/tex]
Now find the y-intercept: the point where the graph crosses the y-axis. The y intercept always has an x value of 0. So -20 is the y-intercept
Use the slope formula [tex]y = mx + b[/tex]. Slope=m, y-intercept = b
y = 15x - 20
y is the money in the bank account in dollars
x is the day
