Question

what we substract from -1 to get 3/5

Answer 1

let y be subtract

then -1-y=3/5
-y=3/5+1
-y=(3+5)/5
-y=8/5
y=-8/5

so let -8/5 should be subtract to get 3/5

Answer 2

let x be subtracted
then
-1-x=3/5
-x=3/5+1
-x=(3+5)5
-x=8/5
x=-8/5

i hope it helpful to u