Answer:
cool
Step-by-step explanation:
 
        
             
        
        
        
This is a problem you need to solve using logs. When you use logs you can "pull" the exponents down in front of the log to get a new equation that looks like this: 2x^3 + x^2 log 81 = 6x - 3 log 27. Now divide both sides by log 81 and 6x - 3 simultaneously to get (2x^3 + x^2)/(6x - 3) = (log 27)/(log 81). If you do the log math on the right side you get .75. Now multiply both sides by 6x-3 to get 2x^3+x^2 = .75(6x-3). If you distribute that out on the left side you'll get 2x^3+x^2=4.5x-2.25. Now move everything over to the left side and set the whole thing equal to 0: 2x^3+x^2-4.5x+2.25=0. When you solve for x, you are in essence factoring, so do this by grouping: x^2(2x+1)-2.25(2x+1). Now finally factor out the 2x+1 to get (2x+1)(x^2-2.25). You're not done yet though cuz you need to solve each of those for x: 2x+1=0, and x= -1/2; x^2=2.25, and x=+/- 1.5. So all the values for x here are -1/2, 1.5, and -1.5
        
             
        
        
        
5cos (2x)+7=cos (2x)+8, 4cos (2x)=1, cos (2x)=1/4, 2x=arccos(1/4), x=(1/2)arccos (1/4). I used x instead of theta, and arccos is cos inverse
        
             
        
        
        
That means they have a common denominator. Hope this helps!
        
                    
             
        
        
        
1) find the lcd the lcd is 12
2)rewrite  the fractions 1/4 and 2/3 using 12 as the denominator (second column) you get 3/12 and 8/12
3) since its confusing to subtract 8/12 from 3/12 you need to borrow one form the 126 doing so is the same as taking 12/12 from 126 this change to 125 and the 12/12 adds to the 3/12 making it 15/12
4) subtract 8/12 form 15/12 to get 7/12
5) subtract 78 form 125 to get 47
6) the answer is 47 7/12