Answer:
1) x= 3i, x= - 3i
2) x= +i , x = - i
, x = - i
Step-by-step explanation:
1) x^2+9=0
(x+3i)(x-3i)=0
x= 3i, x=-3i
2) x^2-4=-11
x^2=-7
x= ±i
x= +i , x = - i
, x = - i
hope this helps!! :))
 
        
             
        
        
        
Answer:
The 99% confidence interval is    
  
Step-by-step explanation:
From the question we are told that 
      The sample size is  n  = 100 
      The sample mean is  
       The population standard deviation is   
  
From the question we are told the confidence level is  99% , hence the level of significance is    
        
=>    
Generally from the normal distribution table the critical value  of   is
 is  
     
Generally the margin of error is mathematically represented as  
       
        
=>     
Generally 95% confidence interval is mathematically represented as  
        
=>      
    
=>      
   
      
 
        
             
        
        
        
Answer:
4/15
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
The correct answer is option A. Base = 11 cm and height = 13 cm
Step-by-step explanation:
It is given that, height of a triangle is 2 cm more than its base.Then height is increased by 2 cm.Then the area of triangle becomes 82.5 cm²
<u>To find the base an d height of original triangle</u>
Let x be the original base 'b' then the height  h = x + 2
New height h = x + 2 + 2 = x + 4
Area = bh/2
82.5= (x(x + 4)/2
165 = x² + 4x
x + 4x - 165 = 0
Solving we get x = 11 and x = -15
Take positive value x = 11
Therefore base = 11 and height = x + 2 = 13 cm
The correct answer is option A. Base = 11 cm and height = 13 cm