The system of equations can be solved using linear combination to eliminate one of the variables.

Which equation can replace [tex][tex]$3x + 5y = 59$[/tex][/tex] in the original system and still produce the same solution?

A. [tex]2x - y = -4[/tex]
B. [tex]10x - 5y = -20[/tex]
C. [tex]7x = 39[/tex]
D. [tex]13x = 39[/tex]



Answer :

To find an equivalent equation that can replace [tex]\(3x + 5y = 59\)[/tex] in the given system without changing the solution, we need to consider the process of elimination and linear combinations.

The original system of equations is:
1. [tex]\(3x + 5y = 59\)[/tex]
2. [tex]\(2x - y = -4\)[/tex]

We want to transform the second equation in such a way that it can replace the first equation but will still maintain the solution. Here's how we can do it:

1. Multiply the second equation by a factor that will help eliminate one of the terms when added to or subtracted from another equation. For instance, by multiplying the second equation by 5, we get:
[tex]\[ 5 \cdot (2x - y) = 5 \cdot (-4) \][/tex]
which simplifies to:
[tex]\[ 10x - 5y = -20 \][/tex]

2. Now we look at our original first equation:
[tex]\[ 3x + 5y = 59 \][/tex]

3. We can now consider adding these two equations together to see if we can eliminate the [tex]\(y\)[/tex] term:
[tex]\[ 3x + 5y = 59 \\ 10x - 5y = -20 \][/tex]
Adding these equations:
[tex]\[ (3x + 10x) + (5y - 5y) = 59 + (-20) \][/tex]
simplifies to:
[tex]\[ 13x = 39 \][/tex]

Thus, adding these modified equations results in the simplified equation:
[tex]\[ 13x = 39 \][/tex]

Therefore, the equivalent equation that can replace [tex]\(3x + 5y = 59\)[/tex] without changing the solution is:
[tex]\[ \boxed{13x = 39} \][/tex]

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