Given that I no not see any explanation in the previos answer, I think you can benefit of this.
Exothermic refers only to the fact that the reaction releases energy in the form of heat when occurs. So, the enthalpy is higher at start and lower and the end.
Seen in this way, you can deduct that the change in enthalpy is negative, which is what the third option says.
You multiply like terms first, which means -2/3x*-x. It becomes 2/3x*3y. The coefficient of x is 2/3. The coefficient of y is 3. You can’t combine them because they are not like terms with the variables.
The equation given in the question is
13 + (w/7) = - 18
(91 + w) / 7 = - 18
91 + w = - 126
w = - 126 - 91
= - 217
I hope that the procedure is clear enough for you to understand. I also hope that this is the answer that you were looking for and the answer has actually come to your desired help.
