Question

How do you find the slope of `2x+8y=9`?

Answer 1

In the general form of a line `y=mx+b`, `m` represents the slope of the line and `b` the y-intercept. Here, we have the line `2x+8y=9`...we want it in the form `y=mx+b` so we can get our `m` (the slope) directly.

To do this, we simply solve `2x+8y=9` for y with some algebra:

`2x+8y=9`
-Take `2x` to the left hand side of the equation by subtracting it from both sides
`8y=9-2x=-2x+9`
-Divide by 8 on both sides of the equation to get y alone
`y=-2/8x+9/8=-1/4x+9/8`

And there we have the line `y=-1/4x+9/8`, with `m=slope=-1/4`