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.
l=51
m=78
n=51
n and l have the same value since it’s an isosceles triangle, so that’s why I doubled 4x-9
Whole package weighs 20pounds
1.65 = 5pounds
0.12 = extra pound
3.45 - 1.65 = 1.80 : 0.12 = 15pounds
Adding up 15pounds and the first 5 pounds equal 20 pounds
Answer: 3rd brand.
Step-by-step explanation:
1st brand:
6 oz cost $1.25
The amount per ounce will be:
= $1.25/6
= $0.21
2nd brand:
8 oz cost $1.33
The amount per ounce will be:
= $1.33/8
= $0.17
3rd brand:
12 oz cost $1.50
The amount per ounce will be:
= $1.50/12
= $0.125
4th brand:
16 oz cost $2.10
The amount per ounce will be:
= $2.10/16
= $0.13
From the calculation, the 3rd brand of orange juice is the better but as it's cheaper than others.
Answer:
Area: ½ × base × height
Perimeter: sum of side lengths of the triangle
of vertices: 3
Number of edges: 3
Internal angle: 60° (for equilateral)
Sum of interior angles: 180°
Step-by-step explanation: