Line Equation 5B4483
1. **State the problem:** Find the equation of the line passing through the points $(-9, 3)$ and $(-3, 7)$ in slope-intercept form $y=mx+b$.
2. **Formula for slope:** The slope $m$ is given by $$m=\frac{y_2 - y_1}{x_2 - x_1}$$ where $(x_1,y_1)$ and $(x_2,y_2)$ are two points on the line.
3. **Calculate the slope:** Using points $(-9,3)$ and $(-3,7)$,
$$m=\frac{7 - 3}{-3 - (-9)}=\frac{4}{6}=\frac{2}{3}$$
4. **Use point-slope form:** The equation is
$$y - y_1 = m(x - x_1)$$
Using point $(-9,3)$,
$$y - 3 = \frac{2}{3}(x + 9)$$
5. **Simplify to slope-intercept form:**
$$y - 3 = \frac{2}{3}x + 6$$
Add 3 to both sides:
$$y = \frac{2}{3}x + 9$$
6. **Verify with another point:** Check point $(-3,7)$:
$$y = \frac{2}{3}(-3) + 9 = -2 + 9 = 7$$ which matches the point.
**Final answer:**
$$y = \frac{2}{3}x + 9$$