1. The problem is to simplify and solve the expression $(r - 7)(r + 6)$ for given values of $r$.
2. The formula used is the distributive property (FOIL method) for multiplying binomials:
$$ (a - b)(a + c) = a^2 + ac - ab - bc $$
3. Applying this to $(r - 7)(r + 6)$:
$$ (r - 7)(r + 6) = r^2 + 6r - 7r - 42 $$
4. Simplify the middle terms:
$$ r^2 - r - 42 $$
5. Now, substitute the given values of $r$:
- For $r = 7$:
$$ 7^2 - 7 - 42 = 49 - 7 - 42 = 0 $$
- For $r = -6$:
$$ (-6)^2 - (-6) - 42 = 36 + 6 - 42 = 0 $$
6. Both values satisfy the expression, confirming the roots $r = 7$ and $r = -6$.
Final answer: The expression simplifies to $$r^2 - r - 42$$ and the roots are $$r = 7$$ and $$r = -6$$.
Binomial Product B961D8
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