A system of equations is given.

[tex]\[
\begin{array}{l}
3y = 20 - 4x \\
2y = 12 - 3x
\end{array}
\][/tex]

Solve for [tex]\((x, y)\)[/tex] using the elimination method. Show all work.



Answer :

Let's solve the given system of equations using the elimination method.

The system of equations is:
[tex]\[ \begin{array}{l} 3y = 20 - 4x \quad \text{(1)} \\ 2y = 12 - 3x \quad \text{(2)} \end{array} \][/tex]

First, we rewrite both equations in standard form [tex]\( Ax + By = C \)[/tex].

For equation (1):
[tex]\[ 3y = 20 - 4x \\ 4x + 3y = 20 \quad \text{(3)} \][/tex]

For equation (2):
[tex]\[ 2y = 12 - 3x \\ 3x + 2y = 12 \quad \text{(4)} \][/tex]

Next, we aim to eliminate one of the variables. Here, we will eliminate [tex]\(y\)[/tex] by making the coefficients of [tex]\(y\)[/tex] in both equations equal.

To make the coefficients of [tex]\(y\)[/tex] the same, we need to find a common multiple of the coefficients of [tex]\(y\)[/tex] (which are 3 and 2). The least common multiple of 3 and 2 is 6.

Multiply equation (3) by 2:
[tex]\[ 2(4x + 3y) = 2(20) \\ 8x + 6y = 40 \quad \text{(5)} \][/tex]

Multiply equation (4) by 3:
[tex]\[ 3(3x + 2y) = 3(12) \\ 9x + 6y = 36 \quad \text{(6)} \][/tex]

Now, subtract equation (5) from equation (6) to eliminate [tex]\(y\)[/tex]:
[tex]\[ (9x + 6y) - (8x + 6y) = 36 - 40 \\ 9x + 6y - 8x - 6y = -4 \\ x = -4 \][/tex]

With [tex]\(x\)[/tex] determined, substitute [tex]\(x = -4\)[/tex] back into equation (3) to find [tex]\(y\)[/tex]:
[tex]\[ 4(-4) + 3y = 20 \\ -16 + 3y = 20 \\ 3y = 20 + 16 \\ 3y = 36 \\ y = 12 \][/tex]

Thus, the solution to the system of equations is:
[tex]\[ (x, y) = (-4, 12) \][/tex]