I don't understand the question


step-by-step explanation:

one of the most important purposes of surface treatment is to alter surface properties according to the requirement of specific applications. for example, hydrophobic coating has been utilized on windshield and eyeglasses. gold atom monolayer on substrate has become a popular surface bioconjugation strategy.  


step-by-step explanation:

7 pigeons sitting on the branches,  5 pigeons under the tree

=12 in total

Step-by-step explanation:

Upper branch has x pigeons, lower has y.

Top branch said: "If one of you flies up to us our number will be double yours":

Well, if one of the bottom branch flies up, the top branch will have x+1 birds and the bottom will have (y−1). The top will have double the bottom, so:


Top branch said: "If one of us flies down to you, our numbers will be equal":

Now, the top branch will have x−1 and the bottom y+1. The numbers should be equal:


Do you know the answer?

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