two points on the graph of a linear functions are (-3,5) and (-1,4). Determine the equation of the function in slope form ?

can someone help explain in step ?
Thanks

(-3,5), (-1,4)

Y = mx + b
m = (y2-y1)/(x2-x1) = (4-5)/(-1-(-3)) =
-1/2 = The slope.

Y = (-1/2)(-3) + b = 5
3/2 + b = 5
b = 5 - 3/2 = 10/2 - 3/2 = 7/2

Eq: Y = (-1/2)x + 7/2