Question

Jack and Jill are trying to find the slope of a line segment connecting two points, (x1, y1) and (x2, y2). Jack uses the formula m = y2 - y1 x2 - x1 . Jill mistakenly uses a different formula, but still gets the right answer. Which formula COULD she have used?

Answer 1

The right formula to get the slope is: m =(y₂-y₁)/(x₂-x₁)
But if you right it the other way round m = (y₁-y₂)/(x₁-x₂)

Both give the same the answer but the 1st is the right one

Answer 2

Slope (
`m_(2)`) =
`((y_(1)-y_(2)))/((x_(1)-x_(2)))`

Explanation:

To find the slope of a line which passes through (
`x_(1),y_(1)`) and (
`x_(2),y_(2)`) we use the formula

Slope (
`m_(1)`) =
`((y_(2)-y_(1)))/((x_(2)-x_(1)))`

Now we will rewrite this formula in another form

Slope (
`m_(2)`) =
`(-(y_(2)-y_(1)))/(-(x_(2)-x_(1)))`

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

If we change the sign of numerator and denominator fraction will remain the same.

Therefore, Slope will remain same and Jill can use this formula to get the value of slope.