Put 0.08kg melting ice to a 0.9kg 20 celsius water.no heat loss,what is the the temperature after?

Well, first of all, YOU need to know your physics formula.
You have to know the specific heat capacity of each these matter, like water and ice.
You should be knowing Q=m x c x change in temperature.
You will have to solve the problem in stages.

If you don't get it. Ask your teacher.<ㅡㅡ The best way.