<h3>
Answer:  130</h3>
Explanation:
Let x be the unknown angle we want to find.
Let y be adjacent and supplementary to x. This means x+y = 180
Let z also be adjacent and supplementary to x. So x+z = 180 also
Subtracting the two equations leads to y-z = 0 and y = z. So effectively we've proven the vertical angle theorem. 
Since the supplementary angles to x add to 100, we know that y+z = 100. Plug in y = z and solve for z
y+z = 100
z+z = 100
2z = 100
z = 100/2
z = 50
Therefore,
x+z = 180
x+50 = 180
x = 180-50
x = 130
 
        
        
        
I'm not sure what you're asking but if you're looking for simplification, here it is. -7x² + 2x - 12
 
        
                    
             
        
        
        
A non-terminating and no -repeating decimal
        
             
        
        
        
I think it's 1.90. I am not fully sure about the answer if it's wrong.
        
             
        
        
        
Lets find out...
our fraction is 1/2.....
when the numerator is increased by 20%......1 + 0.20(1) = 1.2
when the denominator is increased by 50%....2 + 0.50(2) = 3
1/2 = 0.5....original fraction
1.2 / 3 = 0.4.....increased fraction
 decrease = (original number - new number) / original number...* 100
                 = (0.5 - 0.4) / 0.5...* 100
                 = (0.1 / 0.5)....* 100
                = 0.2 * 100
                = 20% decrease <====