André solves the following system of equations by elimination.

[tex]\[
\left\{\begin{array}{c}
3a + 5b = 12 \\
-3a + 5b = -12
\end{array}\right.
\][/tex]

Which could be the resulting equations when André eliminates one of the variables?

A. [tex]12b = 0[/tex]
B. [tex]6a = 0[/tex]
C. [tex]-6a = 0[/tex]
D. [tex]-12b = -24[/tex]



Answer :

Certainly! Let's solve the given system of linear equations using the elimination method step-by-step. The system of equations is:

[tex]\[ \begin{cases} 3a + 5b = 12 \\ -3a + 5b = -12 \end{cases} \][/tex]

Step 1: Adding the Equations

First, let's add the two equations together. Adding the left-hand sides and the right-hand sides, we get:

[tex]\[ (3a + 5b) + (-3a + 5b) = 12 + (-12) \][/tex]

Simplifying both sides, we get:

[tex]\[ 3a - 3a + 5b + 5b = 0 \][/tex]

[tex]\[ 0 + 10b = 0 \][/tex]

This simplifies to:

[tex]\[ 10b = 0 \][/tex]

Dividing both sides by 10, we get:

[tex]\[ b = 0 \][/tex]

Step 2: Substitute [tex]\( b = 0 \)[/tex] into one of the original equations

Now that we have [tex]\( b = 0 \)[/tex], let's substitute [tex]\( b \)[/tex] back into one of the original equations to solve for [tex]\( a \)[/tex]. We can use the first equation:

[tex]\[ 3a + 5b = 12 \][/tex]

Substitute [tex]\( b = 0 \)[/tex]:

[tex]\[ 3a + 5(0) = 12 \][/tex]

Simplify:

[tex]\[ 3a = 12 \][/tex]

Dividing both sides by 3, we get:

[tex]\[ a = 4 \][/tex]

Resulting System

The solutions [tex]\( a = 4 \)[/tex] and [tex]\( b = 0 \)[/tex] satisfy the system. If we focus on the resulting equations from the elimination method, the key resulting equation when eliminating [tex]\( a \)[/tex] was:

[tex]\[ 10b = 0 \][/tex]

Additionally, after isolating [tex]\( b \)[/tex], we further simplified to find:

[tex]\[ a = 4 \][/tex]

Summary of Resulting Equations

- From eliminating [tex]\( a \)[/tex]: [tex]\( 10b = 0 \)[/tex] (or simplified as [tex]\( b = 0 \)[/tex])
- From solving for [tex]\( a \)[/tex]: [tex]\( 3a = 12 \)[/tex]

Thus, the correct answer from the given options would be:

1. [tex]\( 12b = 0 \)[/tex] (derived from [tex]\( b = 0 \)[/tex] after elimination and simplification)

There are no other options needed because we processed through correct elimination and found the unique results appropriate for given coefficients and constants.