9514 1404 393
Answer:

Step-by-step explanation:
Multiply numerator and denominator by the "conjugate" of the denominator.

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This is done in different scenarios in order to take advantage of the factoring of the difference of squares. Square root terms and imaginary terms in the denominator can be eliminated in this way.
a² - b² = (a -b)(a +b)
Answer:
C. $7.70
Step-by-step explanation:
First, you have to calculate the 10% of the price and subtract that from the price to find the amount of the discount:
$27*10%=$2.7
Now, you can add the amount of the discount plus the coupon to find the amount that the customer saved:
$5+$2.7=$7.7
According to this, the answer is that the customer saved: C. $7.70