The answer is 'equal'. Hydroxide ions are OH- and Hydrogen ions are H+. Have you noticed they're opposite charges? Positive + negative = neutral. That's all there is to it :)
So, the answer to 27.) would be <em>2x.</em> Both 6x and 2x can be divided by 2x, but they can't go any higher without the end-answer becoming a fraction. As such, 2x is the greatest common factor.
For 28.), x and x^2 can't be like terms, since like terms have the same variable and exponent :)
Hope I could help!
I believe it's 6789 times 10^4. I could be wrong, due to the fact that I don't remember what's the definition of the scientific notion. I hope this helps, or at least gives you an idea! :D
Your answer would be 58.12g/mol ;)
