Answer: 4/35
Step-by-step explanation: First you need to make the fraction denominators the same so we are going to do multiply 7 x 5 which equals 35 if you don't know your multiplication you can always skip count by 5's so now since we changed the denominators the numerators need to be changes also so the new equation will be 25/35 - 21/35 that equals 4/35 and the fraction cannot be simplified because 1 is the only common divisor