Sum Square
1. **State the problem:** We need to find the value of $$(a+b)^2$$ given that $$a+b=3$$ and $$ab=-2$$.
2. **Recall the identity:** The square of a binomial sum is given by
$$ (a+b)^2 = a^2 + 2ab + b^2 $$
3. **Rewrite using the given sum:** We can express $$a^2 + b^2$$ in terms of $$a+b$$ and $$ab$$ using the identity
$$ a^2 + b^2 = (a+b)^2 - 2ab $$
4. **Calculate using the given values:** Since $$a+b=3$$, we have
$$ (a+b)^2 = 3^2 = 9 $$
Given $$ab = -2$$, then
$$ a^2 + b^2 = 9 - 2(-2) = 9 + 4 = 13 $$
5. **Find the value of $$(a+b)^2$$:** By substituting back,
$$ (a+b)^2 = a^2 + 2ab + b^2 = (a^2 + b^2) + 2ab = 13 + 2(-2) = 13 - 4 = 9 $$
6. **Check:** Since we had $$a+b=3$$, the square of the sum is directly $$3^2=9$$, which matches our calculation.
**Final answer:** $$(a+b)^2 = 9$$