Question

Find the slope of line passing through the point $P(1,-1)$ and $Q(-2,5)$.

Answer 1

Given : $P\equiv (1,-1)=(x_1,y_1)$ and $Q\equiv (-2,5)=(x_2,y_2)$
Then, Slope of line $PQ=\frac{y_2-y_1}{x_2-x_1}$
$=\frac{5-(-1)}{-2-(-1)}$
$=\frac{5+1}{-3}$
$=\frac{6}{-3}$
$=-2$