The line equations are Line a:
, Line b:
, and Line c:
.
Rewrite the equation of line a:
in the slope - intercept form by solving for y.
Add 2x to each side.
\

.
Therefore slope of line a is 2.
Rewrite the equation of line b:
in the slope - intercept form by solving for y.
Subtract 2x from each side.
\


Divide each side by 5.
\

Therefore slope of line b is
.
Rewrite the equation of line c:
in the slope - intercept form by solving for y.
Subtract x from each side.
\


Divide each side by 2.
\\


Therefore slope of line c is
.
Therefore slopes of line a, line b and line c are
respectively.
The line a has a slope of 2, the negative reciprocal of
, so the lines a and c are perpendicular.
The option D is correct answer.