Answer:

Step-by-step explanation:
Given

Required
Determine 

Open bracket

Equate the equation to 0

Express 3 as 1 + 1 + 1

Collect like terms

Group each terms

Factorize (starting with the first bracket)












Express 0 as 0 + 0 + 0

By comparison



Solving for 
Take square root of both sides

Add 1 to both sides


Solving for 
Take square root of both sides

Subtract 1 from both sides


Solving for 
Take square root of both sides

Subtract 1 from both sides


Substitute the values of a, b and c in 



 
        
             
        
        
        
Im pretty sure that it would be 4 but not sure
        
             
        
        
        
Answer:
DE = 6 cm
Step-by-step explanation:
Let DE = x cm.
Since DE is parallel to AB therefore by the alternate interior angles theorem, m∠BAD = m∠ADE and m∠ABE = m∠DEB ............(1)
As AD is an angle bisector of ∠A, therefore m∠EAD = m∠DAB ; Since BE is an angle bisector of ∠B ⇒ m∠ABE = m∠EBD. 
Therefore, from (1) We get ,  m∠EAD = m∠ADE and m∠EBD = m∠BED. 
So, the triangles ADE and EDB are then isosceles with AE = ED and ED = DB. 
So AE = DE = DB = x, and since the perimeter of ABDE is 30 cm, then 
12 + x + x + x = 30
⇒ 12 + 3x = 30
⇒ x = 6
Hence, the length of DE is 6 cm.
 
        
                    
             
        
        
        
Answer:
 x=24
Step-by-step explanation:
 
        
                    
             
        
        
        
Do you have a picture?? Maybe? I’m not good at these