Answer
$l_1$: $-2$
$l_2$: $\dfrac{1}{2}$
$l_3$: $3$
$l_4$: $-\dfrac{1}{4}$
Work Step by Step
We will choose two points on each of the four lines and determine the slope $m$ using their coordinates with the formula:
$$m=\dfrac{y_2-y_1}{x_2-x_1}.$$
Line $l_1$: consider the points $(0,0)$ and $(-2,4)$.
$$m_1=\dfrac{4-0}{-2-0}=-2.$$
Line $l_2$: consider the points $(-4,0)$ and $(4,4)$.
$$m_2=\dfrac{4-0}{4-(-4)}=\dfrac{1}{2}.$$
Line $l_3$: consider the points $(2,-2)$ and $(4,4)$.
$$m_3=\dfrac{4-(-2)}{4-2}=3.$$
Line $l_4$: consider the points $(-2,-1)$ and $(2,-2)$.
$$m_4=\dfrac{-2-(-1)}{2-(-2)}=-\dfrac{1}{4}.$$
