How can you determine if the given lines are perpendicular?

Question

anonymous · Answer

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anonymous · Answer

determine if they have slopes with opposite values
determine if they have the same slope
determine if the product of their slopes is 1
determine if the product of their slopes is –1

jim_thompson5910 · Answer

If their slopes multiply to -1, then the two lines are perpendicular

anonymous · Answer

measure the slope i.e. angle between them.
If the angle is 90 degree. and slope product of lines is 1 then we can say that line are perpendicular

anonymous · Answer

If one line has slope of $m_1$ and other has slope of $m_2$ then the condition of their perpendicularity lies in:
$$m_1 m_2 = -1$$

anonymous · Answer

The slope of line passing from (-3.0) and (3,3 ) is 1/2 while
The slope of line passing from (-1,3) and (3,-3) is -3/2 
the product of this is not equal to -1 hence the are not perpendicular

anonymous · Answer

is it D?