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2. Solve the system of equations using elimination.

[tex]\[
\begin{array}{l}
5x + 6y = 12 \\
2x - 4y = 8
\end{array}
\][/tex]

A. [tex]\((0.5, 3)\)[/tex]
B. [tex]\((3, -0.5)\)[/tex]
C. [tex]\((2, 4)\)[/tex]
D. [tex]\((5, 6)\)[/tex]


Sagot :

Sure, let's solve the system of equations using the elimination method:

1. The system of equations is:
[tex]\[ \begin{array}{l} 5x + 6y = 12 \quad \text{(Equation 1)}\\ 2x - 4y = 8 \quad \text{(Equation 2)} \end{array} \][/tex]

2. First, we'll try to eliminate one of the variables by making the coefficients of [tex]\(x\)[/tex] or [tex]\(y\)[/tex] in both equations the same.

3. We’ll start by eliminating [tex]\(x\)[/tex]. The coefficients of [tex]\(x\)[/tex] in Equation 1 and Equation 2 are 5 and 2, respectively. To make them the same, we can multiply Equation 2 by 5 and Equation 1 by 2:

[tex]\[ 2(5x + 6y) = 2(12) \implies 10x + 12y = 24 \quad \text{(Equation 3)} \][/tex]

[tex]\[ 5(2x - 4y) = 5(8) \implies 10x - 20y = 40 \quad \text{(Equation 4)} \][/tex]

4. Now, subtract Equation 4 from Equation 3 to eliminate [tex]\(x\)[/tex]:

[tex]\[ (10x + 12y) - (10x - 20y) = 24 - 40 \][/tex]

Simplifying, we get:

[tex]\[ 10x + 12y - 10x + 20y = 24 - 40 \][/tex]

[tex]\[ 32y = -16 \][/tex]

Solving for [tex]\(y\)[/tex]:

[tex]\[ y = \frac{-16}{32} = -\frac{1}{2} \][/tex]

5. Now that we have the value of [tex]\(y\)[/tex], we can substitute it back into either Equation 1 or Equation 2 to find the value of [tex]\(x\)[/tex]. We'll use Equation 2:

[tex]\[ 2x - 4(-\frac{1}{2}) = 8 \][/tex]

Simplifying, we get:

[tex]\[ 2x + 2 = 8 \][/tex]

[tex]\[ 2x = 8 - 2 \][/tex]

[tex]\[ 2x = 6 \][/tex]

[tex]\[ x = \frac{6}{2} = 3 \][/tex]

6. Therefore, the solution to the system of equations is [tex]\(x = 3\)[/tex] and [tex]\(y = -\frac{1}{2}\)[/tex], which matches the point [tex]\((3, -0.5)\)[/tex].

So, the correct answer is [tex]\((3, -0.5)\)[/tex].