Answer:
y - b = 1(x - a) - point-slope form
y = x + b - a - slope-intercept form
Explanation:
The point-slope form of an equation of a line:

The formula of a slope:

We have the points (a, b) and (a + 3, b + 3). Substitute:

- point-slope form
Convert to the slope-intercept form: y = mx + b:
add b to both sides
- slope-intercept form