Answer:

Explanation:
We have the slope value of the first line, we will call this

so

And we use the condition so that two lines are perpendicular: the product of the two slopes must be equal to -1.
That is, if the slope of the first line is
and the slope of the second line is
:

we know that
, so:

and clearing for
:

the slope of the line perpendicular to the line with a slope of 2 is:
