Answer
$y=\dfrac{9}{2}x-9.4$
Work Step by Step
Using $y-y_1=\dfrac{y_1-y_2}{x_1-x_2}(x-x_1)$ or the Two-Point Form, then the equation of the line passing through the given points, $(
1.2,-4
)\text{ and }(
3.2,5
)$, is
\begin{array}{l}
y-(-4)=\dfrac{-4-5}{1.2-3.2}(x-1.2)
\\\\
y+4=\dfrac{-9}{-2}(x-1.2)
\\\\
y+4=\dfrac{9}{2}(x-1.2)
\\\\
y+4=\dfrac{9}{2}x-5.4
\\\\
y=\dfrac{9}{2}x-5.4-4
\\\\
y=\dfrac{9}{2}x-9.4
.\end{array}
