write an equation of the line that passes through the given points:

1.(-1,0),(0,-2)

2 answers

m = y2 - y1 / x2 - x1
m = -2 - 0 / 0 - (-1)
m = -2/1
m = -2

point slope form

y - y1 = m (x - x1)
y - 0 = -2 (x - (-1))
y = -2 (x + 1)
y = -2x - 2
the slope of the line is:
(-2 - 0) /( 0 + 1) = -2
the slope of the line is also
(y-0)/(x+1) = slope from any point on the line to (-1,0)
so
y /(x+1) = -2
y = -2 x - 2
-----------------------
now check
0 = -2 (-1) - 2 yes
-2 = -2(0) -2 yes so we got it.