What is the slope of a line that passes through (-2, 2) and (-4, 5) ?
$$\\x_1=-2,~y_1=2 \\
x_2 = -4,~y_2=5\\\\
m=\dfrac{y_2-y_1}{x_2-x_1}\\\\
m=\dfrac{5-2}{(-4)-(-2)}\\\\
m=\dfrac{5-2}{(-4)+2}\\\\
m=\dfrac{5-2}{2-4}\\\\
m=\dfrac{3}{-2}\\\\
m=-\dfrac{3}{2}\\\\
\mathbf{m=-1.5}$$