Question

1. Line L passes through point (-1, 2) and (-3,-2) on a coordinate plane. Line

M passes through the points (1.1) and (-1, W). For what value of W will make
line L and line M parallel.

Answer 1

Slope of a line passing through (
`x_(1)`,
`y_(1)`) and (
`x_(2) , y_(2)`) is given by:

`(y_(2)-y_(1) )/(x_(2)-x_(1))`

Now,

Slope of line L, (m) =
`(-3-(-1))/(-2-2)` = 0.5

Slope of line M, (n) =
`(-1-1)/(W-1)` =
`(-2)/(W-1)`

If the lines L and M are parallel to each other,

m = n

or, 0.5 =
`(-2)/(W-1)`

or, 0.5 (W - 1) = -2

or, W - 1 = -4

or, W = -3

Therefore the required value of W is -3.