To add fractions you want to make sure that the bottom numbers are the same so we have to make them the same, but we have to make sure that the fractions are unchanged so we get the correct answer
so if we find out what number that 9,7, and 5 can all multiply into. we find that 9 times 7 times 5 or 315 is the number that will work
so to get them to all be over 315, we must multiply each fraction by a form of 1/1 or x/x or (number)/(same numbe as on top)
so 7/9 times (35/35)=245/315
1/7 times (45/45)=45/315
3/5 times (56/56)=168/315
we add them togther
245/315+45/315+168/315=(245+45+168)/315=458/315
this simplifies to 1 and 143/315
2➗5 for a division problem and for a fraction it is 2/5
I think its b but i am not surely sure so you might want to check with someone else
