Solve the system of equations using elimination and identify the solution. List your answers in alphabetical order in the ordered pairs.

[tex]\[ 2a + z = 4 \][/tex]
[tex]\[ 3a - 7z = 6 \][/tex]

A. [tex]\((2,0)\)[/tex]
B. [tex]\(\left(\frac{1}{2}, \frac{1}{2}\right)\)[/tex]
C. [tex]\((0,2)\)[/tex]
D. No Solution
E. Infinitely Many Solutions



Answer :

We're given the system of equations:

1) [tex]\(2a + z = 4\)[/tex]

2) [tex]\(3a - 7z = 6\)[/tex]

We will solve this system using the method of elimination.

Step 1: Align the equations for elimination
First, we want to eliminate one of the variables. Let's aim to eliminate [tex]\(z\)[/tex]. To do this, we'll make the coefficients of [tex]\(z\)[/tex] in both equations equal (in magnitude) but opposite in sign.

The coefficients of [tex]\(z\)[/tex] in the first and second equations are 1 and -7, respectively. Let's find a common multiple of these coefficients. The least common multiple of 1 and 7 is 7.

Multiply the first equation by 7 to make the coefficient of [tex]\(z\)[/tex] match (but opposite) that of the second equation:

[tex]\[7(2a + z) = 7 \cdot 4\][/tex]

This gives us:

[tex]\[14a + 7z = 28\][/tex]

Step 2: Rewrite the system
Now we have:

1') [tex]\(14a + 7z = 28\)[/tex]

2) [tex]\(3a - 7z = 6\)[/tex]

Step 3: Add the equations
Adding these two equations will eliminate [tex]\(z\)[/tex]:

[tex]\[ (14a + 7z) + (3a - 7z) = 28 + 6 \][/tex]

Simplify:

[tex]\[14a + 3a + 7z - 7z = 28 + 6\][/tex]

This reduces to:

[tex]\[17a = 34\][/tex]

Step 4: Solve for [tex]\(a\)[/tex]
Divide both sides by 17:

[tex]\[a = \frac{34}{17} = 2\][/tex]

Step 5: Use [tex]\(a\)[/tex] to solve for [tex]\(z\)[/tex]
Now substitute [tex]\(a = 2\)[/tex] back into one of the original equations to solve for [tex]\(z\)[/tex]. We'll use the first equation:

[tex]\[2a + z = 4\][/tex]

Substitute [tex]\(a = 2\)[/tex]:

[tex]\[2(2) + z = 4\][/tex]

[tex]\[4 + z = 4\][/tex]

Subtract 4 from both sides:

[tex]\[z = 0\][/tex]

Step 6: Write the solution as an ordered pair
We've found [tex]\(a = 2\)[/tex] and [tex]\(z = 0\)[/tex]. So the solution to the system is:

[tex]\(\boxed{(2, 0)}\)[/tex]

Therefore, the correct answer is [tex]\((2, 0)\)[/tex].