Answer:
Here's what I get  
Step-by-step explanation:
a. Write an equation
(8x + 12y)² + (6x + 9y)²= (10x + 15y)²
b. Transform the equation
(i) Remove parentheses
64x² +192xy + 144y² + 36x² + 108xy + 81 y² = 100x² +300xy + 225y²
(ii) Combine like terms.
100 x² + 300xy + 225y² = 100x² +300xy + 225y²
The two sides are the same.
The equation is an identity.
 
        
             
        
        
        
Answer:
-55
Step-by-step explanation:
It would be -55 because the exponent is 4. So, that would leave -55 to be the right answer. 
 
        
             
        
        
        
Answer:
Step-by-step explanation:
Compare the ratios of the triangles like so:
Bigger to smaller

This statement is true. Both fractions simplified are equal to 1.5. Since they have the same ratios, they should be similar. 
 
        
             
        
        
        
Answer:
The volume of the metal used is 5277.9 cm³.
Step-by-step explanation:
The volume of a cylinder is given by:

Where:
r: is the radius
h: is the height = 50 cm
The volume of metal ( ) can be found by subtracting the internal volume (
) can be found by subtracting the internal volume ( ) from the external volume (
) from the external volume ( ):
):

 
     
The external radius is given by the sum of the internal radius with the tickness:

Hence, the volume is:

            
Therefore, the volume of the metal used is 5277.9 cm³.
I hope it helps you!                                                      
 
        
             
        
        
        
Answer:
7x+12y
Step-by-step explanation:
Simplify
4x+9y+3(x+y)
<em>Use the distributive property to multiply 3 by x+y.
</em>
4x+9y+3x+3y
<em>Combine 4x and 3x to get 7x.
</em>
7x+9y+3y
<em>Combine 9y and 3y to get 12y.
</em>
7x+12y