Get the information you need with the help of IDNLearn.com's extensive Q&A platform. Join our community to receive prompt and reliable responses to your questions from experienced professionals.

Solve the system of equations:

[tex]\[
\left\{
\begin{array}{l}
-x + 3y = -8 \\
x - 4y = 9
\end{array}
\right.
\][/tex]


Sagot :

Let's solve the system of linear equations step by step:

[tex]\[ \left\{ \begin{array}{l} -x + 3y = -8 \\ x - 4y = 9 \end{array} \right. \][/tex]

Step 1: Isolate one variable in one of the equations. Let's isolate [tex]\(x\)[/tex] in the second equation:

[tex]\[ x - 4y = 9 \][/tex]

Add [tex]\(4y\)[/tex] to both sides:

[tex]\[ x = 4y + 9 \][/tex]

Step 2: Substitute this expression for [tex]\(x\)[/tex] into the first equation:

[tex]\[ -(4y + 9) + 3y = -8 \][/tex]

Distribute the negative sign:

[tex]\[ -4y - 9 + 3y = -8 \][/tex]

Combine like terms:

[tex]\[ -4y + 3y - 9 = -8 \][/tex]

[tex]\[ -y - 9 = -8 \][/tex]

Add 9 to both sides:

[tex]\[ -y = 1 \][/tex]

Multiply by -1 to solve for [tex]\(y\)[/tex]:

[tex]\[ y = -1 \][/tex]

Step 3: Substitute [tex]\(y = -1\)[/tex] back into the expression we found for [tex]\(x\)[/tex]:

[tex]\[ x = 4y + 9 \][/tex]

[tex]\[ x = 4(-1) + 9 \][/tex]

[tex]\[ x = -4 + 9 \][/tex]

[tex]\[ x = 5 \][/tex]

So, the solution to the system of equations is:

[tex]\[ x = 5, \quad y = -1 \][/tex]

Thus, the solution is [tex]\((x, y) = (5, -1)\)[/tex].