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What is the solution to the system of equations below?

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

A. [tex]\( x = 2, y = -2 \)[/tex]
B. [tex]\( x = -2, y = 3 \)[/tex]
C. [tex]\( x = 4, y = 4 \)[/tex]
D. [tex]\( x = -2, y = 1 \)[/tex]


Sagot :

To solve the system of equations:
[tex]\[ \begin{cases} x + 4y = -2 \\ x - 4y = -8 \end{cases} \][/tex]

We can use the method of addition (or elimination) to eliminate one of the variables.

1. Add the two equations together:

[tex]\[ (x + 4y) + (x - 4y) = -2 + (-8) \][/tex]

This simplifies to:

[tex]\[ x + x + 4y - 4y = -2 - 8 \][/tex]

Which further simplifies to:

[tex]\[ 2x = -10 \][/tex]

2. Solve for [tex]\(x\)[/tex]:

[tex]\[ 2x = -10 \implies x = \frac{-10}{2} \implies x = -5 \][/tex]

3. Substitute [tex]\(x = -5\)[/tex] back into one of the original equations to find [tex]\(y\)[/tex]:

Using the first equation, [tex]\(x + 4y = -2\)[/tex]:

[tex]\[ -5 + 4y = -2 \][/tex]

4. Solve for [tex]\(y\)[/tex]:

Add 5 to both sides to isolate the term with [tex]\(y\)[/tex]:

[tex]\[ 4y = -2 + 5 \][/tex]

[tex]\[ 4y = 3 \][/tex]

Divide both sides by 4:

[tex]\[ y = \frac{3}{4} \][/tex]

Thus, the solution to the system of equations is:

[tex]\[ x = -5, \; y = \frac{3}{4} \][/tex]

The solution does not match any of the given options directly. However, verifying our solution by plugging [tex]\(x = -5\)[/tex] and [tex]\(y = \frac{3}{4}\)[/tex] back into the original equations confirms that the solved values are correct. Thus, the provided answer choices might involve a mistake.

Nevertheless, the correct solution is:

[tex]\[ x = -5, \; y = \frac{3}{4} \][/tex]

Since none of the given multiple-choice options are correct as provided, it would be best to check the problem statement or the answer choices again.