You can put this solution on YOUR website! Explain why are the following lines perpendicular y= -4 over 5x +7 and y= 5 over 4x -12
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They're perpendicular because the angle at the intersection is 90 degs.
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If you mean to ask what indicates that, the slopes are negative inverses, or the product of their slopes = -1.
m1 * m2 = -1
m1 = -1/m2
