Write the equation of the line which passes through (2, - 1) and is perpendicular to the line with equation 5y - x = 1.

Solve 5y - x = 1 for y such that y = mx + b so we can extract the slope.

y = 1/5x + 1/5

Perpendicular lines have opposite signed reciprocal slopes.

1/5 would have an opposite signed (-) reciprocal (5) slope of - 5

Now let's find b by substituting the values of y, m, and x into y = mx + b:

-1 = - 5 (2) + b

-1 = - 10 + b

9 = b

So the equation is y = - 5x + 9 or 5x + y = 9