Equations of Lines (HSC SSCE Mathematics Advanced): Flashcards

$y - y_1 = m(x - x_1)$

Gradient of the line

A point on the line

$m = \frac{y_2 - y_1}{x_2 - x_1}$

$m_1 = m_2$

$m_1 \times m_2 = -1$

Negative reciprocal: $m_2 = -\frac{1}{m_1}$

$y = mx + c$

Same as original line's gradient

Negative reciprocal of original gradient