How do you find the slope of a line perpendicular to y=7/5x-2y=75x−2?

1 Answer
vince
Jun 20, 2015

The slope is -5/7−57

Explanation:

The slope of your line is 7/575, therefore a director vector of your line is, for example, vec{AB} (5,7)−−→AB(5,7) (because the slope is (Delta y) /(Delta x)).

The vector vec{u} (-7,5) is orthogonal with vec{AB} because dot product is null : 5 \times(-7) + 7\times 5 = 0.

Finally, the slope is (Delta y) /(Delta x) = 5/-7 = - 5/7.

Remark. You need orthonormal system for the equation of the line. But I suppose it is :-)

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