The table can be used to determine the solution to the system of equations, [tex]2y - x = 8[/tex] and [tex]y - 2x = -5[/tex].

\begin{tabular}{|l|l|l|l|l|l|}
\hline
\begin{tabular}{l}
Original \\
System
\end{tabular} &
\begin{tabular}{c}
Equivalent \\
System
\end{tabular} &
\begin{tabular}{c}
Sum of \\
Equations in \\
Equivalent \\
System
\end{tabular} &
\begin{tabular}{c}
Solution to \\
System
\end{tabular} &
\begin{tabular}{c}
New \\
System \\
Using Sum
\end{tabular} &
\begin{tabular}{c}
Solution to \\
New \\
System
\end{tabular} \\
\hline
\begin{tabular}{l}
[tex]2y - x = 8[/tex] \\
[tex]y - 2x = -5[/tex]
\end{tabular} &
\begin{tabular}{l}
[tex]2y - x = 8[/tex] \\
[tex]-2y + 4x = 10[/tex]
\end{tabular} &
\begin{aligned}
[tex]2y - x = 8[/tex] \\
[tex]3x = 18[/tex]
\end{aligned} &
& & \\
\hline
\end{tabular}

Which solution can be used to fill in both blanks in the table?

A. (1, 6)
B. (6, 1)
C. (7, 6)
D. (6, 7)



Answer :

To solve the system of equations [tex]\( 2y - x = 8 \)[/tex] and [tex]\( y - 2x = -5 \)[/tex], we follow these steps:

1. Original System:
[tex]\[ \begin{cases} 2y - x = 8 \\ y - 2x = -5 \\ \end{cases} \][/tex]

2. Equivalent System:
The first equation remains the same:
[tex]\[ 2y - x = 8 \][/tex]
Multiply the second equation by 2 to facilitate elimination:
[tex]\[ 2(y - 2x) = 2(-5) \\ -2y + 4x = -10 \][/tex]
Therefore, the equivalent system is:
[tex]\[ \begin{cases} 2y - x = 8 \\ -2y + 4x = -10 \\ \end{cases} \][/tex]

3. Sum of Equations in Equivalent System:
Add the two equations:
[tex]\[ (2y - x) + (-2y + 4x) = 8 + (-10) \\ 2y - x - 2y + 4x = -2 \\ 3x = -2 \][/tex]

4. Solution to System:
Solve for [tex]\(x\)[/tex]:
[tex]\[ x = \frac{-2}{3} \][/tex]

5. Using [tex]\(x\)[/tex] to Find [tex]\(y\)[/tex]:
Substitute [tex]\( x = 6 \)[/tex] into the first equation to find [tex]\( y \)[/tex]:
[tex]\[ 2y - 6 = 8 \\ 2y = 14 \\ y = 7 \][/tex]
So, the solution to the system is [tex]\( \boxed{(6, 7)} \)[/tex].

6. New System Using Sum:
Using the sum [tex]\( 3x = 18 \)[/tex] to find [tex]\(x\)[/tex]:
[tex]\[ x = \frac{18}{3} = 6 \][/tex]
Substitute [tex]\( x = 6 \)[/tex] into the first equation:
[tex]\[ 2y - 6 = 8 \\ 2y = 14 \\ y = 7 \][/tex]
Thus, the solution to the new system is also [tex]\( \boxed{(6, 7)} \)[/tex].

Therefore, the solution that can be used to fill in both blanks in the table is [tex]\((6, 7)\)[/tex].

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