Finding the equation of a line (AQA GCSE Further Maths): Flashcards

$y = mx + c$

The gradient (slope)

The y-intercept

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

When you know gradient and y-intercept

When you know the gradient and one point on the line

Calculate the gradient using the two points

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

$\frac{y - y_1}{y_2 - y_1} = \frac{x - x_1}{x_2 - x_1}$

$y = mx$

$ax + by + c = 0$

Sign errors