$\"\"$

\

\

Slope of the two non vertical lines is $\"\"$

\

Replace $\"\"$ in slope formula.

\

$\"\"$

\

$\"\"$ (Subtract: $\"\"$ ) $\"\"$

\

$\"\"$ (Multiply each side by 3)

\

$\"\"$ (Cancel common terms)

\

$\"\"$ (Simplify)

\

$\"\"$ (Add -4 to each side)

\

$\"\"$ (Add: $\"\"$ )

\

$\"\"$ \ \ $\"\"$

\

Check:

\

To check the solution, substitute $\"\"$ in original equation.

\

$\"\"$

\

$\"\"$ (Subtract: $\"\"$ )

\

$\"\"$ (Divide: $\"\"$ )

\

Compare the values, the equation is true.

\

$\"\"$

\

The value of $\"\"$ .

\

\

\