Line Equation 54E546
1. **State the problem:** Find the equation of the straight line passing through the points $(-2,8)$, $(0,0)$, and $(2,-8)$.
2. **Formula used:** The equation of a line can be found using the slope-intercept form:
$$y = mx + b$$
where $m$ is the slope and $b$ is the y-intercept.
3. **Calculate the slope $m$:** The slope between two points $(x_1,y_1)$ and $(x_2,y_2)$ is
$$m = \frac{y_2 - y_1}{x_2 - x_1}$$
Using points $(-2,8)$ and $(0,0)$:
$$m = \frac{0 - 8}{0 - (-2)} = \frac{-8}{2} = -4$$
4. **Find the y-intercept $b$:** Since the line passes through $(0,0)$, the y-intercept is
$$b = 0$$
5. **Write the equation:** Substitute $m = -4$ and $b = 0$ into the slope-intercept form:
$$y = -4x + 0$$
or simply
$$y = -4x$$
6. **Verify with the third point $(2,-8)$:** Substitute $x=2$:
$$y = -4(2) = -8$$
which matches the given point, confirming the equation is correct.