Find the equation of the line that is perpendicular to y = –2x + 5 and contains the point
(2,–1).

The given equation is:

To find the line perpendicular to it, we interchange coefficients and switch the signs of one coefficient.

The equation to a line perpendicular to it is:

$ 2y-x=c$

where, $c$ is some constant we have determine using the condition given.

It passes through $(2,-1)$

Put the point in our equation:

$2(-1)-(2)=c$

$c=-2-2$

$c=-4$

The final equation is:

$\boxed{ 2y-x=-4}$