Answer:
B
Step-by-step explanation:
x²+2x=19 add 1 to both sides which gives you x²+2x+1=20
x²+2x+1 is the same as (x+1)²
Therefore (x+1)²=20
 
        
             
        
        
        
Answer:
36
Step-by-step explanation:
Data provided in the question:
Standard error = 1.5 minutes             ( ∵ number are repetitive 1.51.5 )  
Standard deviation = 9 minutes        ( ∵ number are repetitive 99 )
Now,
Standard error = ( Standard deviation ) ÷ √n
Here,
n is the sample size
Therefore,
on substituting the respective values, we get
1.5 = 9 ÷ √n
or
√n = 9 ÷ 1.5
or
√n = 6
or
n = 6² = 36
 
        
             
        
        
        
Answer:
14-2a
Step-by-step explanation:
Since 15 and 21 are not included: we will have
=15-2a-1
=14-2a
 
        
             
        
        
        
Answer:
5/3 or 1.67
Step-by-step explanation:
Find the slope of the original line
 3x+5y=4                Subtract 3x from both sides
5y = - 3x + 4           Divide both sides by 5
y = (-3/5)x + 4
The original line has a slope of - 3/5 or - 0.6
Find the slope of the perpendicular line
m1 * m2 = - 1
m1 = - 3/5
m2 = -1/(-3/5)
m2 = 5/3
The slope of the perpendicular line is
5/3 or 1.67
 
        
             
        
        
        
Line r is twice line m. i.e. r = 2s which means that they are linearly dependent.
Therefore there are infinitely many solution to the given set of equations.