I think this is the Transitive postulate of equality.
Personally I can't see much point in giving labels to these equalities.
Answer:
yea that makes sense
It literally tells you how to do it
Is it some kind of proof tho? Like the math makes sense but like I've never heard of this thing.
The equation of line parallel to
and containing the point(-10,-3) is 
Step-by-step explanation:
We need to write the equation parallel to
and containing the point(-10,-3)
The standard form of point slope equation is:

where m is slope and b is y-intercept
Comparing the given equation
with standard form the slope is m= -1/5
Since the lines are parallel the slope of new line is m = -1/5
Now finding b (y-intercept)
Using slope m=-1/5 and point (-10,-3)

So, b= -5 and slope = -1/5 the equation of new line is:

So, The equation of line parallel to
and containing the point(-10,-3) is 
Keywords: Point Slope form
Learn more about point slope form at:
#learnwithBrainly
Answer:

Step-by-step explanation:
The standard form of an equation is when both variables, x & y, are on the same side of the equation with a number on the other side.
To transform this equation from slope-intercept form to standard form, just switch sides for the y and the 9 like follows.

I hope this helped you :D