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Find the equation of a line perpendicular to line 2y = 5x...

Find the equation of a line perpendicular to line 2y = 5x + 4 which passes through (4, 2).

A.

5y - 2x -18 = 0

B.

5y + 2x - 18 = 0

C.

5y - 2x + 18 = 0

D.

5y + 2x - 2 = 0

Correct answer is B

2y = 5x + 4 (4, 2)

y = \(\frac{5x}{2}\) + 4 comparing with

y = mx + e

m = \(\frac{5}{2}\)

Since they are perpendicular

m1m2 = -1

m2 = \(\frac{-1}{m_1}\) = -1

\(\frac{5}{2}\) = -1 x \(\frac{2}{5}\)

The equator of the line is thus

y = mn + c (4, 2)

2 = -\(\frac{2}{5}\)(4) + c

\(\frac{2}{1}\) + \(\frac{8}{5}\) = c

c = \(\frac{18}{5}\)


y = -\(\frac{2}{5}\)x + \(\frac{18}{5}\)

5y = -2x + 18

or 5y + 2x - 18 = 0