A trapezoid is isosceles if and only if 
(1)	The base angles are congruent
(2)	The diagonals are congruent
(3)	The opposite angles are supplementary
So the description does not guarantee that a trapezoid is isoceles for "Congruent bases".
 
        
             
        
        
        
Answer:
5) 15120
6) 11880
7) 336
Step-by-step explanation:
The formula for permutation where mPn is m!/(m-n)!
Applying this to question 5, we get 9!/4!, which is 15120.
For question 6, we get 12!/8!, which is 11880.
For question 7, we get 8!/5!, which is 336.
 
        
             
        
        
        
Answer: 1) 25b   2) ac   3)ba
1) Since b is unknown, your answer will be 25b
2) Since both variables, a and c, are unknown, your answer will be ac
3) Since both are unknown here, it will be ba!
 
        
             
        
        
        
Answer:  7(3m - 7n)
<u>Step-by-step explanation:</u>
Factor each term then see what value(s) they have in common:
           21m         -          49n
             ∧                        ∧
           3 · 7 · m              7 · 7 · n
Both terms have a 7 in common.  What is left over after removing the 7?
21m: 7(3m)
49n: 7(7n)
GCF: 7           Leftovers: 3m <em>and</em>  7n
Factored form of expression is: 7(3m - 7n)
 
        
                    
             
        
        
        
Answer:
$286.80
Step-by-step explanation:
First, find the price after the 150% markup:
478(1.5)
= 717
Now, calculate the price with the 60% discount:
717(0.4)
= 286.8
= $286.80