47 -14i
You can work this out in the straight-forward way, or you can recognize that (6-i) is a common factor. In the latter case, you have ...
... = (6-i)(5 + 3-i)
... = (6 -i)(8 -i)
This product of binomials is found in the usual way. Each term of one factor is multiplied by each term of the other factor and the results summed. Of course, i = √-1, so i² = -1.
... = 6·8 -6i -8i +i²
... = 48 -14i -1
... =
_____
A suitable graphing calculator will work these complex number problems easily.
Answer:
see the explanation
Step-by-step explanation:
<em><u>The question is </u></em>
Identify the domain and the range, using words and inequalities
Let
x -----> the number of kilowatt-hours (kWh) of electricity per month
y ----> the price per month
we know that
Part 1) For the value of x between 0 kWh and 400 kWh
The price is equal to
therefore
The domain is the interval ------> [0,400)
The domain is all real numbers greater than or equal to 0 kWh and less than 400 kWh
The range is ($30)
The range is equal to $30
Part 2) For the value of x equal to 400 kWh or more per month
The domain is the interval -----> [400, infinite)
The domain is all real numbers greater than or equal to 400 kWh
The price is
<em>Find the range</em>
For x=400 kWh
so
The range is the interval -----> [38.8, infinite)