Question

HELP!!!!!! What is the equation of the line that is perpendicular to y = one-fifth x + 4 and that passes through (5,–4)?

Answer 1

$y = mx + b \\ \\ m = \frac{ - 1}{a} = \frac{ - 1}{ \frac{1}{5} } = - 5 \\ y = - 5x + b \\ passes \: through \: (5 \: , - 4)$

$- 4 = - 5(5) + b \\ b = - 4 + 25 = 21 \\ \\ y = - 5x + 21$