See photo for solution and mark me as brainliest if i helped :) 
A: although it seems like they are forming a 90º angle, they actually add up to a 89 º angle and therefore are not complementary 
B: see photo
 
        
        
        
The triangles are shown to be similar, therefore

The answer is 9 units
 
        
        
        
From the problem :

In multiplying expressions with the same bases, the exponent will be added accordingly.
For example :

the exponent of a are m and n, and the product will be a raised to the sum of m and n.
Applying this to the problem, we have :

The answer is d. 6^-1
 
        
             
        
        
        
Answer:
5cm  = r
Step-by-step explanation:
The area of a circle is given by
A = pi r^2
78.5 = 3.14 r^2
Divide each side by 3.14
78.5/ 3.14 = r^2
25 = r^2
Take the square root of each side
sqrt(25) = sqrt(r^2)
5 = r
 
        
                    
             
        
        
        
<span>B. 2d^2+6d-7. Should be the correct answer.</span>