Which ordered pair [tex]\((p, r)\)[/tex] is the solution to the given system of linear equations?

[tex]\[
\begin{cases}
5p - 3r = 1 \\
8p + 6r = 4
\end{cases}
\][/tex]

A. [tex]\((-1, -2)\)[/tex]

B. [tex]\((-2, -1)\)[/tex]

C. [tex]\(\left(\frac{2}{9}, \frac{1}{3}\right)\)[/tex]

D. [tex]\(\left(\frac{1}{3}, \frac{2}{9}\right)\)[/tex]



Answer :

To find the solution for the given system of linear equations:

[tex]\[ \begin{cases} 5p - 3r = 1 \\ 8p + 6r = 4 \end{cases} \][/tex]

we need to determine the values of [tex]\( p \)[/tex] and [tex]\( r \)[/tex] that satisfy both equations simultaneously.

### Step 1: Write down the equations
1. [tex]\( 5p - 3r = 1 \)[/tex]
2. [tex]\( 8p + 6r = 4 \)[/tex]

### Step 2: Normalize one of the equations, if possible
From the second equation, we can divide every term by 2 to simplify it:
[tex]\[ 4p + 3r = 2 \][/tex]

### Step 3: Rewrite the system
This changes our system to:
[tex]\[ \begin{cases} 5p - 3r = 1 \\ 4p + 3r = 2 \end{cases} \][/tex]

### Step 4: Add the equations
To eliminate [tex]\( r \)[/tex], add the two equations together:
[tex]\[ (5p - 3r) + (4p + 3r) = 1 + 2 \][/tex]

The [tex]\( -3r \)[/tex] and [tex]\( +3r \)[/tex] cancel each other out:
[tex]\[ 5p + 4p = 3 \][/tex]
[tex]\[ 9p = 3 \][/tex]

### Step 5: Solve for [tex]\( p \)[/tex]
Divide both sides of the equation by 9:
[tex]\[ p = \frac{3}{9} = \frac{1}{3} \][/tex]

### Step 6: Substitute [tex]\( p \)[/tex] back into one of the original equations
Use the first equation to solve for [tex]\( r \)[/tex]:
[tex]\[ 5p - 3r = 1 \][/tex]
Substitute [tex]\( p = \frac{1}{3} \)[/tex]:
[tex]\[ 5\left(\frac{1}{3}\right) - 3r = 1 \][/tex]
[tex]\[ \frac{5}{3} - 3r = 1 \][/tex]

### Step 7: Solve for [tex]\( r \)[/tex]
Isolate [tex]\( r \)[/tex] by moving the fraction to the other side:
[tex]\[ \frac{5}{3} - 1 = 3r \][/tex]
[tex]\[ \frac{5}{3} - \frac{3}{3} = 3r \][/tex]
[tex]\[ \frac{2}{3} = 3r \][/tex]
Divide both sides by 3:
[tex]\[ r = \frac{2}{3 \cdot 3} = \frac{2}{9} \][/tex]

### Step 8: Conclusion
The solution to the system of equations is:
[tex]\[ \left( p, r \right) = \left( \frac{1}{3}, \frac{2}{9} \right) \][/tex]

So, the correct ordered pair is [tex]\( \left( \frac{1}{3}, \frac{2}{9} \right) \)[/tex]. This matches the option: [tex]\( \left( \frac{1}{3}, \frac{2}{9} \right) \)[/tex].