Expand Polynomial
1. Let's state the problem: simplify the expression $(3r-2s)(3r-2s)(3r-2s)(3r-2s)$.
2. Notice that this is the same factor $(3r-2s)$ multiplied by itself four times, so it is $(3r-2s)^4$.
3. To simplify $(3r-2s)^4$, it is easier to first find $(3r-2s)^2$ and then square the result.
4. Calculate $(3r-2s)^2 = (3r-2s)(3r-2s)$. Use the distributive property:
$$ (3r)(3r) - (3r)(2s) - (2s)(3r) + (2s)(2s) = 9r^2 - 6rs - 6rs + 4s^2 $$
5. Combine like terms:
$$ 9r^2 - 12rs + 4s^2 $$
6. Now, the original expression becomes
$$ (3r-2s)^4 = ig((3r-2s)^2ig)^2 = (9r^2 - 12rs + 4s^2)^2 $$
7. Next, expand $(9r^2 - 12rs + 4s^2)^2$ using the formula for the square of a trinomial $(a-b+c)^2 = a^2 - 2ab + 2ac + b^2 - 2bc + c^2$:
$$ (9r^2)^2 - 2 imes 9r^2 imes 12rs + 2 imes 9r^2 imes 4s^2 + (-12rs)^2 - 2 imes (-12rs) imes 4s^2 + (4s^2)^2 $$
8. Calculate each term:
- $(9r^2)^2 = 81r^4$
- $-2 imes 9r^2 imes 12rs = -216r^3 s$
- $2 imes 9r^2 imes 4s^2 = 72r^2 s^2$
- $(-12rs)^2 = 144r^2 s^2$
- $-2 imes (-12rs) imes 4s^2 = 96r s^3$
- $(4s^2)^2 = 16s^4$
9. Add all terms together:
$$ 81r^4 - 216r^3 s + 72r^2 s^2 + 144r^2 s^2 + 96r s^3 + 16s^4 $$
10. Combine like terms $72r^2 s^2 + 144r^2 s^2 = 216r^2 s^2$:
$$ 81r^4 - 216r^3 s + 216r^2 s^2 + 96r s^3 + 16s^4 $$
This is the fully expanded form of $(3r-2s)^4$.
Final answer: $$81r^4 - 216r^3 s + 216r^2 s^2 + 96r s^3 + 16s^4$$