3(x^2 -x) -x
6x^2 -3x-x
6x^2 - 4x
we can simplify it more by take 2x as comman factor
so , 2x ( 3x -2 )
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.
Yes that is true because -3=3 so -3 is less
Petri dish A has 1080000000000000
Petri dish B has 270000000000
Petri dish a is greater by 1.07973E15
Hope that helped :)