What is the equation of a line that passes through (2, -1) and is parallel to the line 2x-y=1

Question

Find the equation of the line

Answer 1

2x - y = 1

2x = y + 1

y = 2x - 1

slope = 2

parallel line, so the slope is the same.  

we want a line with slope = 2, going through point (2,-1)

point-slope form

y - y1 = m (x - x1)

y - -1 = 2 (x - 2)

y + 1 = 2 (x - 2)

y + 1 = 2x - 4

y = 2x - 5