Step-by-step explanation:
Hey there!
The equation of a st.line passing through points (4,5) and (8,9) is;
[tex](y - y1) = \frac{y2 - y1}{x2 - x1} (x - x1)[/tex]
Put all values.
[tex](y - 5) = \frac{9 - 5}{8 - 4} (x - 4)[/tex]
Simplify them to get equation.
[tex](y - 5) = \frac{4}{4} (x - 4)[/tex]
[tex](y - 5) = 1(x - 4)[/tex]
[tex](y - 5) = x - 4[/tex]
[tex]x - y + 1 = 0[/tex]
Therefore the required equation is: x - y + 1=0.
Hope it helps...