Review the graphs of a system of two linear equations in two variables: x−5y=7 and 3x−2y=−4 . Find the solution to both equations

1 answer

To find the solution to the system of equations given by:

  1. \( x - 5y = 7 \)
  2. \( 3x - 2y = -4 \)

we can use either the substitution method or the elimination method. Here, I'll use the substitution method.

Step 1: Solve the first equation for \( x \)

From the first equation:

\[ x = 5y + 7 \]

Step 2: Substitute for \( x \) in the second equation

Now, substitute \( x \) from the first equation into the second equation:

\[ 3(5y + 7) - 2y = -4 \]

Step 3: Distribute and simplify

Distributing \( 3 \):

\[ 15y + 21 - 2y = -4 \]

Combine like terms:

\[ (15y - 2y) + 21 = -4 \] \[ 13y + 21 = -4 \]

Step 4: Isolate \( y \)

Subtract \( 21 \) from both sides:

\[ 13y = -4 - 21 \] \[ 13y = -25 \]

Now, divide both sides by \( 13 \):

\[ y = -\frac{25}{13} \]

Step 5: Substitute back to find \( x \)

Substitute \( y \) back into the equation \( x = 5y + 7 \):

\[ x = 5\left(-\frac{25}{13}\right) + 7 \]

Calculating \( 5 \cdot -\frac{25}{13} \):

\[ x = -\frac{125}{13} + 7 \] \[ x = -\frac{125}{13} + \frac{91}{13} \] \[ x = -\frac{125 - 91}{13} \] \[ x = -\frac{34}{13} \]

Final Solution

The solution to the system of equations is:

\[ \left( -\frac{34}{13}, -\frac{25}{13} \right) \]

This means that the point \( \left( -\frac{34}{13}, -\frac{25}{13} \right) \) is the point where the two lines intersect, which is the solution to the system.