Given the system of equations.
\[
\left\{\begin{array}{l}
4 x+y=8 \\
6 x-9 y=12
\end{array}\right.
\]
Which of the options represents the resulting equation ater an equiblett expeasion for yis s.bsutut int the second equation?
$6 x-9 \mid-4 x+8)=12$
$6(4 x-8)-9 y=12$
$4 x+4 x-8=8$
$6 x-94 x-8)=12$

Answer

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Answer

Simplify the equation to get the final answer: $\boxed{42x - 72 = 12}$

Steps

Step 1 ：Given the system of equations: \[\left\{\begin{array}{l} 4 x+y=8 \\ 6 x-9 y=12 \end{array}\right.\]

Step 2 ：Express y in terms of x from the first equation: $y = 8 - 4x$

Step 3 ：Substitute this expression into the second equation in place of y: $6x - 9(8 - 4x) = 12$

Step 4 ：Simplify the equation to get the final answer: $\boxed{42x - 72 = 12}$