On the last statement of your Visa Card, your balance was $625.00. You paid $225.00. Your credit card company uses the previous balance method to
compute your finance charge and the periodic rate is 1.5%. You make a
purchase of $72.00. What is your new balance?
Finance Charge = Previous Balance x
Periodic Rate
New Balance = Previous Balance + Finance
Charge + New Purchases - (Payments +
Credits)

The scenario will be as following

The general from of the line ⇒  y = mx + c
where m is the slope and c is constant and represent the y intercept

The given line is ⇒ y = -0.8 x + 5.6
So, the slope of the line = m = -0.8 
note: the slope of the line is negative which mean as x increase y decrease

To find y-intercept we need to substitute with x = 0
∴ y = -0.8* 0 + 5.6 = 5.6 
So, the y - intercept is the point (0,5.6)

and to find the x - intercept we need to substitute with y = 0
∴ 0 = -0.8x + 5.6
∴ x = 5.6/0.8 = 7
So, the x intercept is the point (7,0)

See the attached figure which represent the graph of the given equation.