The sum of the interior angles of a triangle is 180 degrees
2x-9+3x+x+3=180
6x-6=180
6x=186
x=31
A=2(31)-9
A=62-9
A=53
        
             
        
        
        
Answer: -2x+14
Step-by-step explanation: use the distributive property. -2 times x and -2 times -7. -2x+14
 
        
                    
             
        
        
        
If  68  is a prime number, then the only factors it has are  1  and  68.
If it has any other factors besides  1  and  68, then it's NOT prime.
Right away, without any higher math, you can look at just the last digit 
in 68 .  The last digit is '8'.  That tells you that '68' is an even number, 
and THAT tells you that '2' must be one of its factors.  So '68' is not a 
prime number. 
The factors of  68  are  1,  2,  4,  17,  34, and  68 .     
68  has four more factors besides  1  and  68, so it's not a prime number.
        
                    
             
        
        
        
So you can you the Pythagorean theorem to solve this problem.
if each side of the square is a certain length x, then the square is made up of two right triangles.
the sides adjacent to the right angle are length x while the hypoteneus is the diagonal whcih measures 36 feet.
a^2 + b^2 = c^2
x^2 + x^2 = 36^2
2x^2 = 1296
x^2 = 648
x = 25.456
area of a square = x^2 = 648 ft^2
        
             
        
        
        
Note that if 

, then 

, and so we can collapse the system of ODEs into a linear ODE:


which is a pretty standard linear ODE with constant coefficients. We have characteristic equation

so that the characteristic solution is

Now let's suppose the particular solution is 

. Then

and so

Thus the general solution for 

 is

and you can find the solution 

 by simply differentiating 

.