Question: I need to find a line passes through the points (-10,-4) (-1,2) which is the y-intercept of the line?
1. (0,8/3)
2. (9/3,0)
3.(0,-4)
4. (-4,0)
The equation of a line passing through the two points (x1,y1), (x2,y2) is given by,
(y-y1)/(x-x1) = (y2-y1)/(x2-x1)
When (x1,y1) = (-10, -4) and (x2,y2) = (-1, 2), then
(y-(-4))/(x-(-10)) = (2-(-4))/((-1)-(-10))
(y + 4)/(x +10) = (6)/(9) = 2/3
3(y + 4) = 2(x + 10)
3y + 12 = 2x + 20
3y = 2x + 8
y = (2/3)x + 8/3
The y-intercept of the above line (which is when x = 0) is y = 8/3.
Answer: Choice 1. (0,8/3)