# 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?

Aug 10, 2017

$y = 2 x + 8$

#### Explanation:

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

$y - {y}_{1} = m \left(x - {x}_{1}\right)$

$y - 8 = 2 \left(x - 0\right)$

$y - 8 = 2 x$

$y = 2 x + 8$