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What should be the first step in adding these equations to eliminate [tex]y[/tex]?

[tex]\[
\begin{array}{l}
8x + 3y = 2 \\
4x - 6y = -7 \\
\end{array}
\][/tex]

A. Multiply the top equation by 2.

B. Multiply the bottom equation by 8.

C. Multiply the top equation by 4.

D. Multiply the bottom equation by 2.


Sagot :

The goal is to eliminate [tex]\(y\)[/tex] by adding the two given equations together. Here are the equations:

[tex]\[ \begin{array}{l} 8x + 3y = 2 \\ 4x - 6y = -7 \\ \end{array} \][/tex]

To eliminate [tex]\(y\)[/tex], the coefficients of [tex]\(y\)[/tex] in both equations should be opposites.

1. The coefficient of [tex]\(y\)[/tex] in the first equation is 3.
2. The coefficient of [tex]\(y\)[/tex] in the second equation is -6.

If we multiply the entire first equation by 2, we will get the coefficient of [tex]\(y\)[/tex] in the first equation to be 6, which is the opposite of -6.

The first equation, when multiplied by 2, becomes:

[tex]\[ 2(8x + 3y) = 2(2) \implies 16x + 6y = 4 \][/tex]

Now, we have:

[tex]\[ \begin{array}{l} 16x + 6y = 4 \\ 4x - 6y = -7 \\ \end{array} \][/tex]

Adding these two equations together will now eliminate [tex]\(y\)[/tex]:

[tex]\[ (16x + 6y) + (4x - 6y) = 4 + (-7) \implies 20x = -3 \][/tex]

Therefore, the first step in adding these equations to eliminate [tex]\(y\)[/tex] is:

A. Multiply the top equation by 2.