Answer:
12 hours
Step-by-step explanation:
Step one:
given data
base fee= $60
charge per hour= $15
let the number of hours the plumber work be x
the linear function for the charge is the equation of line.
that is y=mx+c
Step two:
given that y=$240
240=15x+60
240-60=15x
180=15x
divide both sides by 15 we have
x=180/15
x=12
<u>The number of hours is 12</u>
Answer:
The solutions for the given system of equations are:

Step-by-step explanation:
Given the equation system:

We obtain the following matrix:
![\left[\begin{array}{cccc}3&1&4&-3\\-1&1&4&17\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D3%261%264%26-3%5C%5C-1%261%264%2617%5Cend%7Barray%7D%5Cright%5D)
<u>Step 1:</u> Multiply the fisrt row by 1/3.
![\left[\begin{array}{cccc}1&\frac{1}{3} &\frac{4}{3}&-1\\-1&1&4&17\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%26%5Cfrac%7B1%7D%7B3%7D%20%26%5Cfrac%7B4%7D%7B3%7D%26-1%5C%5C-1%261%264%2617%5Cend%7Barray%7D%5Cright%5D)
<u>Step 2:</u> Sum the first row and the second row.
![\left[\begin{array}{cccc}1&\frac{1}{3} &\frac{4}{3}&-1\\0&\frac{4}{3} &\frac{16}{3}&16\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%26%5Cfrac%7B1%7D%7B3%7D%20%26%5Cfrac%7B4%7D%7B3%7D%26-1%5C%5C0%26%5Cfrac%7B4%7D%7B3%7D%20%26%5Cfrac%7B16%7D%7B3%7D%2616%5Cend%7Barray%7D%5Cright%5D)
<u>Step 3:</u> Multiply the second row by 3/4.
![\left[\begin{array}{cccc}1&\frac{1}{3} &\frac{4}{3}&-1\\0&1 &4&12\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%26%5Cfrac%7B1%7D%7B3%7D%20%26%5Cfrac%7B4%7D%7B3%7D%26-1%5C%5C0%261%20%264%2612%5Cend%7Barray%7D%5Cright%5D)
<u>Step 4:</u> Multiply the second row by -1/3 and sum the the first row.
![\left[\begin{array}{cccc}1&0 &0&-5\\0&1 &4&12\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D1%260%20%260%26-5%5C%5C0%261%20%264%2612%5Cend%7Barray%7D%5Cright%5D)
The result of the reduced matrix is:

This is equal to:

These are the solutions for the system of equations in terms of z, where z can be any number.
Answer:
the answer is D
Step-by-step explanation:
makes sense...
Answer:
Answer b
Step-by-step explanation:
Mark brainliest