Answer:
Step-by-step explanation:
The slope is the ratio of the change in y to the change in x:
m = ((b+3) -b)/((a +3) -a) = 3/3 = 1
The point-slope form of the equation of a line through point (h, k) with slope m is ...
y -k = m(x -h)
Here, we have (h, k) = (a, b) and m=1, so the equation in point-slope form is ...
y -b = x -a
Adding b puts this in slope-intercept form:
y = x + (b-a)