Question

Which statement is the negation of the following statement?
"If two lines are perpendicular to a single line, then they are parallel."
If two lines are not parallel, then they are not perpendicular to two lines.
If two lines are not parallel, then they are not perpendicular to a single line.
If two lines are not perpendicular to a line, then they are not parallel.
If two lines are not perpendicular to a line, then neither is perpendicular to another line.

Answer 1

You started with a conditional. If p then q. So the negation statement must be of the form if p then not q. the contrapositive statement has the same truth table.

Answer 2

thanks!