Question

How do you find a standard form equation for the line with (-1, 5), parallel to x + y = 10?

Answer 1

`y=-x`

Explanation:

We need a line parallel to `y=10-x` passing through `(-1,5)`. Parallel lines have the same gradient, so our required line will have a gradient of `-1`.

Now we need to use the formula to find the equation of a line given two points and the gradients:

`y-y_1=m(x-x_1)`

`y-5=-(x+5)`

`y-5=-x-5`

`y=-x`