Please, in the future, post just one problem at a time.
Looking at Problem #1: The line intersects the y-axis at (0,-3) and intersects the x-axis at (1,-1). At least, this is what I see; your graph is small.
-3-[-1]
The slope of that line is then m = rise / run = ------------ = +2.
0 - 1
[change in y]
Slope = m = rise / run = --------------------
[change in x]
The point-slope form:

We have the points
and
.
Substitute:

The standard form: Ax + By = C

Answer:
The second one
Step-by-step explanation:
Your one is the correct
No because a right triangle always has a right angle