Answer :
so solve for r
try to isolate the placeholder
1+r/9=0
subtract 1 from both sides
r/9=-1
multiply both sides by 9 to clear fraction (because r/9 times 9/1=r/1 times 9/9=r)
r=-9
tada
try to isolate the placeholder
1+r/9=0
subtract 1 from both sides
r/9=-1
multiply both sides by 9 to clear fraction (because r/9 times 9/1=r/1 times 9/9=r)
r=-9
tada