Question

What is the equation of the line with an `x`-intercept of -1 and a `y`-intercept of 2?

Answer 1

`y = 2x + 2`

Explanation:

The equation of any (non-vertical) line can take the form `y = ax+b` where `a` is the slope and `b` is the `y` intercept. We know that in this case, the `y` intercept is `2`. So we can substitute `b=2`:

`y = ax + 2`. Now, to find the `x` intercept, simply put `y=0` (since every point on the `x` axis has `y=0`) and `x=-1`, since that is the given `x` intercept:

`0 = -a + 2`, so we see that `a = 2`. The equation is then:

`y = 2x + 2`