Enclosed Area
1. **State the problem:** Find the area enclosed by the curves given by the equations $$y = 5x + 4$$ and $$y = x^2 + 2x - 6$$.
2. **Find the points of intersection:** Set the two equations equal to find the x-values where the curves intersect.
$$5x + 4 = x^2 + 2x - 6$$
Rearrange to form a quadratic equation:
$$x^2 + 2x - 6 - 5x - 4 = 0$$
$$x^2 - 3x - 10 = 0$$
3. **Solve the quadratic equation:**
Use the quadratic formula $$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$ where $$a=1$$, $$b=-3$$, and $$c=-10$$.
$$x = \frac{-(-3) \pm \sqrt{(-3)^2 - 4(1)(-10)}}{2(1)} = \frac{3 \pm \sqrt{9 + 40}}{2} = \frac{3 \pm \sqrt{49}}{2}$$
$$x = \frac{3 \pm 7}{2}$$
So the two intersection points are:
$$x = \frac{3 + 7}{2} = 5$$ and $$x = \frac{3 - 7}{2} = -2$$.
4. **Set up the integral for the area:**
The area enclosed is the integral of the difference between the upper curve and the lower curve from $$x = -2$$ to $$x = 5$$.
Since $$y = 5x + 4$$ is a line and $$y = x^2 + 2x - 6$$ is a parabola, check which is on top between the intersection points.
Test at $$x=0$$:
$$5(0) + 4 = 4$$
$$0^2 + 2(0) - 6 = -6$$
So, $$y = 5x + 4$$ is above $$y = x^2 + 2x - 6$$ between $$x = -2$$ and $$x = 5$$.
5. **Calculate the area:**
$$\text{Area} = \int_{-2}^{5} \left[(5x + 4) - (x^2 + 2x - 6)\right] dx = \int_{-2}^{5} (-x^2 + 3x + 10) dx$$
6. **Integrate:**
$$\int (-x^2 + 3x + 10) dx = -\frac{x^3}{3} + \frac{3x^2}{2} + 10x + C$$
7. **Evaluate the definite integral:**
$$\left[-\frac{x^3}{3} + \frac{3x^2}{2} + 10x\right]_{-2}^{5} = \left(-\frac{5^3}{3} + \frac{3 \cdot 5^2}{2} + 10 \cdot 5\right) - \left(-\frac{(-2)^3}{3} + \frac{3 \cdot (-2)^2}{2} + 10 \cdot (-2)\right)$$
Calculate each part:
$$-\frac{125}{3} + \frac{3 \cdot 25}{2} + 50 = -\frac{125}{3} + \frac{75}{2} + 50$$
$$= -41.6667 + 37.5 + 50 = 45.8333$$
$$-\frac{-8}{3} + \frac{3 \cdot 4}{2} - 20 = \frac{8}{3} + 6 - 20 = 2.6667 + 6 - 20 = -11.3333$$
Subtract:
$$45.8333 - (-11.3333) = 45.8333 + 11.3333 = 57.1666$$
8. **Round to 2 decimal places:**
$$\boxed{57.17}$$
**Final answer:** The area enclosed by the curves is approximately 57.17 square units.