Answer:
The standard enthalpy of formation is the energy that would be involved if one mole of the substance were to be formed from its elements that were at standard conditions of temperature and pressure which are 25 degrees C and one atm pressure.
Step-by-step explanation:
Answer:
If the problem is asking
then the answer is 4
If it's asking
then the answer is 
Step-by-step explanation:
To solve for y, apply the distributive property:

Then, subtract 12 from both sides and you will get:

Then solve for y, by dividing both sides by 10.
Your final answer will be y=1.2
Answer:
x=3
Step-by-step explanation:
First, combine like terms on the left side
4x-5x+9=5x-9
-x+9=5x-9
Subtract 9 on both sides
-x=5x-18
Subtract 5x on both sides
-6x= -18
Divide by -6 on both sides
x=3
Hope this helps! :)
First one single solution second no solution 3rd one single forth one infinity and last 2 are single and infinity