Determine the slope of a line passing through 2 points. Used $m=$ $x_{1-x2}$ $y_{1-y2}$ $-$ $or$ $m=\dfrac {y2-y1} {x_{2-x_{1}}}$ $1$ $\left(1.2\right)$ and $\left(5.5\right)$ $2$ $\left(-5.-5\right)$ and $\left(-5.5\right)$ $3$ $\left(-5.4\right)$ and $\left(5,1\right)$ $4$ $5$ $\left(-2,1\right)$ $\left(-3.-4\right)$ and $\left(6,1\right)$ and $\left(5.4\right)$