Theory:
The standard form of set-builder notation is <span>
 
{ x | “x satisfies a condition” } </span>
This set-builder notation can be read as “the set
of all x such that x (satisfies the condition)”.
For example, { x | x > 0 }  is
equivalent to “the set of all x such that x is greater than 0”.
 
Solution:
In the problem, there are 2 conditions that must
be satisfied:
<span>1st: x must be a real number</span>
In the notation, this is written as “x ε R”.
Where ε means that x is “a member of” and R means “Real number”
 
<span>2nd: x is greater than or equal to 1</span>
This is written as “x ≥ 1”
 
Answer:
Combining the 2 conditions into the set-builder
notation:
<span>
X =
{ x | x ε R and x ≥ 1 } </span>
 
        
                    
             
        
        
        
Answer:
25.5   and   37.5 
Step-by-step explanation:
x+y=63
x-y = 12    then   x = 12 + y      sub this into the first equation
(12+y)    + y = 63 
12 + 2y = 63
2y = 51
y = 25.5     then x = 37.5 
 
        
             
        
        
        
Answer:
 27.8 degrees
Step-by-step explanation:
Wasn't it 'a,' not 'A,' that you wanted?
The ratio a/ 30 is the cosine of the angle 22 degrees, which in turn is 0.927:
                           a
Then 0.927 = -------    which yields a = 30(0.927) = 27.8 degrees
                          30
 
        
             
        
        
        
Answer:
(x − 7)(x + 3)
Step-by-step explanation:
Step 1: You need to find out what to numbers add up to −4 and multiply −21?
−7 and 3
Step 2: Just rewrite the expression using the above and you're done!
(x − 7)(x + 3)