Answer:
Option 4
The answer is 10.8
Step-by-step explanation:
5/6 = 9/c
5c = 9 × 6
5c = 54
5c/5 = 54/5
c = 10.8
Thus, The value of c is 10.8
<h3>
<u>For </u><u>Verification</u>;</h3>
5/6 = 9/c
5/6 = 9/10.8
0.833 = 0.833
Hence, L.H.S = R.H.S
<u>-TheUnknownScientist</u><u> 72</u>
 
        
             
        
        
        
I’m guessing you mean like this.
2x+4y+5x+8y.
2x and 5x are like terms because the x’s are alike. If you add 2+5, the answer is 7. So therefore 2x+5x=7x.
4y and 8y are like terms because the y’s are alike. So the answer to 4y+8y would be 12y.
If you need extra help, give me a problem and I will help you solve it.
        
             
        
        
        
Answer:  
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Work Shown:
Apply the following trig identity

Now let's rationalize the denominator

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As confirmation, you can use the idea that if x = y, then x-y = 0. We'll have x = tan(165) and y = -2+sqrt(3). When computing x-y, your calculator should get fairly close to 0, if not get 0 itself. 
Or you can note how

which helps us see that they are the same thing.
Further confirmation comes from WolframAlpha (see attached image). They decided to write the answer as  but it's the same as above.
 but it's the same as above.
 
        
             
        
        
        
This equation would be represented as a No Solution equation. Due to the fact that if you do inverse operation and combine like terms, your variables will cancel out.