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Solve the system of equations below.

[tex]\[
\begin{aligned}
-3x + 6y &= 9 \\
5x + 7y &= -49
\end{aligned}
\][/tex]

A. [tex]\(\left(-2, \frac{1}{2}\right)\)[/tex]
B. [tex]\((1, -2)\)[/tex]
C. [tex]\((-2, -7)\)[/tex]
D. [tex]\((-7, -2)\)[/tex]



Answer :

GinnyAnswer
To solve the system of equations

[tex]\[ \begin{aligned} -3x + 6y &= 9 \\ 5x + 7y &= -49 \end{aligned} \][/tex]

we aim to find the values of [tex]\(x\)[/tex] and [tex]\(y\)[/tex] that satisfy both equations simultaneously. Here's a step-by-step solution:

1. Rewrite the first equation:
[tex]\[ -3x + 6y = 9 \][/tex]
This can be divided by 3 for simplicity:
[tex]\[ -x + 2y = 3 \quad \text{(Equation 1')} \][/tex]

2. Rewrite the second equation:
[tex]\[ 5x + 7y = -49 \quad \text{(Equation 2)} \][/tex]

3. Solve Equation 1' for [tex]\(x\)[/tex]:
[tex]\[ -x + 2y = 3 \implies x = 2y - 3 \][/tex]

4. Substitute [tex]\(x = 2y - 3\)[/tex] into Equation 2:
[tex]\[ 5(2y - 3) + 7y = -49 \][/tex]
Simplify this expression:
[tex]\[ 10y - 15 + 7y = -49 \][/tex]
Combine like terms:
[tex]\[ 17y - 15 = -49 \][/tex]
Solve for [tex]\(y\)[/tex]:
[tex]\[ 17y = -49 + 15 \][/tex]
[tex]\[ 17y = -34 \][/tex]
[tex]\[ y = -2 \][/tex]

5. Use [tex]\(y = -2\)[/tex] to solve for [tex]\(x\)[/tex]:
Substitute [tex]\(y = -2\)[/tex] back into Equation 1':
[tex]\[ x = 2(-2) - 3 \][/tex]
Simplify the expression:
[tex]\[ x = -4 - 3 \][/tex]
[tex]\[ x = -7 \][/tex]

So, the solution to the system of equations is [tex]\(x = -7\)[/tex] and [tex]\(y = -2\)[/tex].

Hence, the correct answer is:

D. [tex]\((-7, -2)\)[/tex]

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