Slope of the two non vertical lines is .
Replace in slope formula.
(Subtract:
)
Apply multiplication property of equality: Multiply each side by k2.
(Cancel common terms)
Apply division property of equality: Divide each side by negative 2.
\ (Cancel common terms)
Apply addition property of equality: a=b then a+c = b+c.
\ (Add 2 to each side)
(Add:
)
Check:
\To check the solution, substitute in original equation.
(Subtract:
)
(Cancel common terms)
Compare the values, the equation is true.
The value of .