Question

What is the equation of the line that passes through (1,2) and is parallel to the line whose equation is 2x+y-1=0

Answer 1

put:
2x + y - 1 = 0
into "slope-intercept" form:
2x + y - 1 = 0
2x + y = 1
y = -2x + 1
now, we know the slope is -2
"parallel" lines must have the same slope
use -2 and (1,2) to populate
"point-slope" form:
y - y1 = m(x - x1)
y - 2 = -2(x - 1)
y - 2 = -2x + 2
y = -2x + 4 (slope-intercept form)
2x + y -4 = 0 (standard form) (answer)