s + t over 5 + 2(s + t) over 15

[wanda57]

s + t over 5 + 2(s + t) over 15

 

[arthur ohlsten]

[s+t]/5 + 2[s+t] /15
place both terms over common denominator 15
3[s+t]/15 +2[s+t]/15
place over common denominator
{ 3[s+t]+2[s+t] } /15
combine , or factor out [s+t]
5[s+t]/15
divide numerator and denominator by 5
[s+t]/3 answer
Arthur