Answer: Fast
Just k1dding, in terms of setting up an equation for it, we know that 8.75 is the slope coefficient with months and 75 is the intercept.
So basically amount charged = monthly service fee(# months) + bank account base
Or with numbers
Amount charged = 8.75(num months) + 75.00
Now plug in 7 months
8.75(7)+75.00 = 61.25+75.00= $131.25.