Step by step
The question
Question: write the line through (2, 6) with slope 1 in point-slope form.
1 Rise = m × run
We call the slope m.
m = rise over run.
So the rise is m times the run.
Like 8/2 is 4, so 8 is 4 times 2.
Take any point (x, y) on the line.
We go from (2, 6) to (x, y).
The rise is y − 6: the change in y.
The run is x − 2: the change in x.
Put them in: rise = m × run becomes y − 6 = (x − 2).
This is called point-slope form.
It is made from a point and the slope.
m = 1, and 1 times a bracket is just the bracket.
2 Write as y = mx + b
A bracket with a plus or nothing in front can just be removed.
Now we have y − 6 = x − 2.
We want y by itself.
The − 6 is in the way.
To remove − 6, we add 6.
We do it on both sides, so they stay equal.
− 6 and + 6 make zero.
Cross them out.
−2 plus 6 is 4.
So y = x + 4.
3 Check
Let's check: put x = 2 into y = x + 4.
We get 6, the y of (2, 6).
And the number in front of x is 1: the slope.
Right!
Let's look back.
First: rise = m × run.
Then: write as y = mx + b.
Last: check.