we know that
The slope-intercept form of a linear equation is
[tex]y=mx+b[/tex]
where
m is the slope
b is where the line crosses the y-axis
Solve the equation for the slope
[tex]y=mx+b[/tex]
Subtract [tex]b[/tex] both sides
[tex]y-b=mx+b-b[/tex]
[tex]y-b=mx[/tex]
Divide by [tex]x[/tex] both sides
[tex](y-b)/x=mx/x[/tex]
[tex]m=(y-b)/x[/tex]
therefore
the answer is
[tex]m=(y-b)/x[/tex]