The form of the linear equation is
[tex]y=mx+b[/tex]m is the slope
b is the y-intercept
Since the slope of the line is 1, then
m = 1
Substitute it in the form of the equation above
[tex]\begin{gathered} y=(1)x+b \\ y=x+b \end{gathered}[/tex]To find b substitute x and y in the equation by the coordinates of a point on the line
Since the line contains the point (4, 1), then put
x = 4 and y = 1
[tex]1=4+b[/tex]Subtract 4 from both sides to find b
[tex]\begin{gathered} 1-4=4-4+b \\ -3=b \end{gathered}[/tex]Substitute the value of b in the equation
[tex]\begin{gathered} y=x+(-3) \\ y=x-3 \end{gathered}[/tex]The equation of the line is y = x - 3