Question

In the coordinate plane, O is the origin. A is a point on the y-axis, and B is is a point on the x-axis. The slope of AB is 2 and its y-intercept is 8. What is the line equation for AB?

Answer 1

`y = 2x + 8`

Explanation:

Utilise the point-gradient formula to find the equation of the line. Since the y-intercept is 8, that point is `(0, 8)`. The slope is defined as the 'gradient' or the `m` value. Therefore, `m=2`. We can substitute in these values.

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

`y - 8 = 2(x - 0)`

`y - 8 = 2x`

`y = 2x + 8`