1. **State the problem:** Solve $a^3+a^2=36$ for $a$.
2. **Write the equation in standard form:**
$$a^3+a^2-36=0$$
3. **Look for a simple integer solution by testing factors of $36$:**
Since the constant term is $-36$, try $a=3$.
$$3^3+3^2=27+9=36$$
So $a=3$ is a solution.
4. **Factor the polynomial using $a=3$:**
$$a^3+a^2-36=(a-3)(a^2+4a+12)$$
Check by expanding:
$$ (a-3)(a^2+4a+12)=a^3+4a^2+12a-3a^2-12a-36=a^3+a^2-36 $$
5. **Set each factor equal to zero:**
$$a-3=0 \quad \text{or} \quad a^2+4a+12=0$$
So one solution is:
$$a=3$$
6. **Check the quadratic for real solutions:**
$$a^2+4a+12=0$$
Use the discriminant:
$$b^2-4ac=4^2-4(1)(12)=16-48=-32$$
Because the discriminant is negative, the quadratic has no real roots.
7. **Final answer:**
$$a=3$$
Cubic Equation 81Bc01
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.