Okay so basically your next months credit card charge will be 100% of your previous balance plus an added 1.4%. Which is 101.4%. Then you subtract the $75 from that balance.
Is.      =.     %
Of.             100
X         = 101.4
(1407.64).     100
Cross multiply 
100x= 142734.696
Divide by 100
1427.34696 - 75(the money you are going to pay)
=1352.34696
Which will be approximately 1352.35