$9.78=100%
$9.65=?
9.65*100/9.78
=98.67%
%decrease=100%-98.67%
=1.33%
=1.3%
I believe it's 9.1 Hope this helps :)
The equation of the line in point-slope form is given by:

Where,
(xo, yo): point that belongs to the line
m: slope of the line
The slope is given by:

Substituting values:

Rewriting:

Now we choose an ordered pair:

Substituting values we have:

We now rewrite the equation in its standard form:

Where,
b: cut with the y axis.
We have then:
Answer: point-slope form: 
or
standard form