Answer:
f(320)= how much Dereck pays for phone service if he calls 320 minutes.
F(320)=0.11(320)+43=35.2+43=78.2
Answer: the value of f(320) is $78.2 and it will be the cost of phone service for 320 minutes of international calls.
Answer:
x= 3
y=2
Step-by-step explanation:
-3x + 9y = 9 ----------- equation 1
3x + 2y = 13--------------- equation 2
In Matrix Form
![\left[\begin{array}{cc}-3&9\\3&2\end{array}\right] \left[\begin{array}{c}x\\y\end{array}\right] = \left[\begin{array}{c}9\\13\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D-3%269%5C%5C3%262%5Cend%7Barray%7D%5Cright%5D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx%5C%5Cy%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D9%5C%5C13%5Cend%7Barray%7D%5Cright%5D)
Let A = ![\left[\begin{array}{cc}-3&9\\3&2\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D-3%269%5C%5C3%262%5Cend%7Barray%7D%5Cright%5D)
X = ![\left[\begin{array}{c}x\\y\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx%5C%5Cy%5Cend%7Barray%7D%5Cright%5D)
and B = ![\left[\begin{array}{c}9\\13\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D9%5C%5C13%5Cend%7Barray%7D%5Cright%5D)
Then Mathematically AX= B
or X= A⁻¹ B
Where A⁻¹ = Adjacent A/ mod of A
Adjacent A = ![\left[\begin{array}{cc}2&-9\\-3&-3\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D2%26-9%5C%5C-3%26-3%5Cend%7Barray%7D%5Cright%5D)
Mod Of A= -6 - (27) = -33 which is not equal to zero
so Putting These values in the given formula
X= 1/-33
Now Multiplying Rows and Columns
= -1/33 ![\left[\begin{array}{cc}2*9+- 9*13\\-3*9 +- 3*13\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D2%2A9%2B-%209%2A13%5C%5C-3%2A9%20%2B-%203%2A13%5Cend%7Barray%7D%5Cright%5D)
Solving the Matrix we get
= -1/33 ![\left[\begin{array}{cc}18-117\\-27-39\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D18-117%5C%5C-27-39%5C%5C%5Cend%7Barray%7D%5Cright%5D)
= -1/33 ![\left[\begin{array}{cc}-99\\-66\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D-99%5C%5C-66%5Cend%7Barray%7D%5Cright%5D)
From Here we find x= 99/33 or 3
and y = 66/33= 2
Answer:
B
Step-by-step explanation:
.4 as we know can also be handled as .40, as the zero helps us determine the difference in value. 50%, though it is a percentage, can be put into decimal form. That would be .5, or again, we could add a zero to help us out, which would make it .50. As of right now, .4 is less than 50%. 3 and 13 are whole numbers, so they do not really need deep observation, except that 3 is less than 13. That would make the order of number from least to greatest .4, 50%, 3, and 13.
It’s the same now in decimals is 2.35215804 it goes on
The answer is 128. Sorry I’m really bad at explaining
