Question

Are 7 and 8 right. Plz help

Answer 1

The seven is  not right must be 
15:(1+2)=5        first the pharentesis 15:3=5
They way that you put the answer of the seven is not correct, the pharentesis is not needed in the case like you use it because anyway (without pharentesis in other places) the division go first that the sum 
and the eight is correct