1. **State the problem:** We need to determine the equation of the line passing through the points (-10, -15) and (10, 15). 2. **Recall the formula for the slope of a line:** $$m = \frac{y_2 - y_1}{x_2 - x_1}$$ where $(x_1, y_1)$ and $(x_2, y_2)$ are two points on the line. 3. **Calculate the slope:** $$m = \frac{15 - (-15)}{10 - (-10)} = \frac{15 + 15}{10 + 10} = \frac{30}{20}$$ 4. **Simplify the slope:** $$m = \frac{\cancel{30}}{\cancel{20}} = \frac{3}{2} = 1.5$$ 5. **Use the point-slope form of a line equation:** $$y - y_1 = m(x - x_1)$$ Using point $(-10, -15)$: $$y - (-15) = 1.5(x - (-10))$$ 6. **Simplify the equation:** $$y + 15 = 1.5(x + 10)$$ $$y + 15 = 1.5x + 15$$ 7. **Subtract 15 from both sides:** $$y + 15 - 15 = 1.5x + 15 - 15$$ $$y = 1.5x$$ **Final answer:** The equation of the line is $$y = 1.5x$$