Use the FOIL method
First 4x × -2x = -8x^2
Outside 4x × -5 = -20x
Inside 3 × -2x = -6x
Last 3 × -5 = -15
-8x^2 - 20x - 6x -15 =
Combine like terms
-8x^2 -26x -15
Step-by-step explanation:
do 425÷5 and you will get your answer
Answer:
<em>The final price including tax is $41.89</em>
Step-by-step explanation:
The following items are on sale:
Sleeved dress $17.99
Skirt $16.19
T-shirt $8.99
Subtotal $43.17
The cheapest item is the T-shirt for $8.99 and it will be discounted by 30%:
$8.99 - 30/100 * $8.99 = $8.99 - $2.70 = $6.29
The total sale price is now: $43.17-$2.70=$40.47
Now we add the 3.5% tax:
$40.47 + 3.5/100 * $40.47 = $40.47 + $1.42 = $41.89
The final price including tax is $41.89
If 32.16 includes the sales tax....then the price before the sales tax will be less then 32.16
that only leaves 2 choices.....
so lets check them...
7% sales tax on 2.25 = 0.07(2.25) = 0.16....so if u spent 2.25 on groceries and added the sales tax of 16 cents....then u would have spent 2.41...thats a long way from 32.16
if u spent 30.06...with 7% sales tax....u would spend 30.06 + 0.07(30.06) = 32.16
so the cost of the groceries before the sales tax is 30.06 <==
Explanation:
a)
b) First, we have that
On the other hand,
Therefore, both expressions are equal. This makes sense, because selecting k elements from a group of n is the same than specify which elements you will not select. In order to specify those elements you need to select the n-k elements that will not be selected. Hence, each time you are selecting k from n, you are also selecting n-k from n, and from that reason both combinatorial numbers are equal.
