Ok first you need to get a common denominator of 3 and 5 the smallest one would be 15 so then you rewrite both but remember if you do something to the bottom u have to do it to the top so you multiplied 3by 5 to get 15 to get your bottom then you have to times 5by 1 to get 5. So 5/15,same process for 3/5
5/15+ 9/15=9+5=14 so 14/15 (you keep the bottom the same) also it doesn’t need to be simplified because nothing can go into 14and 15 evenly
Same process for subtracting just subtract in the end so...
30/35-14/35= 16/35 also can’t be simplified evenly
In the end your answers are
1.14/15
2.16/35