<span>Each team in the softball league plays each of the other teams exactly once. For every game, there is 2 team playing. The order is not important because  A vs B is same as B vs A
So you just need to makes a combination of 2 that have a result of 21. If there is t number of teams, the number of matches would be:
tC2 = t!/2!(t-2)! = 21
</span>t! / (t-2)! = 21 *2
(t)(t-1)= 42
t^2 -t -42=0
(t-7)(t+6)
t=7 ; t=-6
Excluding the minus result, you got 7 teams.
        
             
        
        
        
Answer:

Step-by-step explanation:

The fractions have unlike denominators. First, find the Least Common Denominator and rewrite the fractions with the common denominator.
 ×
 ×  +
 +  ×
 ×
Complete the multiplication and the equation becomes

The two fractions now have like denominators so you can add the numerators.

This fraction can be reduced by dividing both the numerator and denominator by the Greatest Common Factor of 14 and 12 using
GCF(14,12) = 2
14÷2 / 12÷2 =7/6
The fraction
7/6
is the same as
7÷6
Convert to a mixed number using
long division for 7 ÷ 6 = 1R1, so
7/6= 
Therefore:
3/4 − (−5/12) = 
Solution by Formulas
Apply the fractions formula for subtraction, to
3/4 − (−5/12)
and solve
(3×12) − (−5×4) 4×12
=3/6− (−20/48)
=56/48
Reduce by dividing both the numerator and denominator by the Greatest Common Factor GCF( 56,48) = 8
56÷8 / 48÷8 =7/6
Convert to a mixed number using
long division for 7 ÷ 6 = 1R1, so
7/6= 
Therefore:
3/4 − (-5/12) = 
 
        
             
        
        
        
-7x - 2y = 19
4x + y = -12
Set y equal to each other (opposite signs are fine and you could also set x equal instead of y)
-7x - 2y = 19
8x + 2y = -76
Add equations together
x = -52
Plug x value into an equation
4(-52) + y = -12
Solve for y
-208 + y = -12
y = 196
Hope this helps! ;)
 
        
             
        
        
        
The equation would be -9+-9 = -18
 
        
                    
             
        
        
        
Answer:
7x + 7
Step-by-step explanation:
2x + 5x = 7x
5 +2 = 7