To prove that the expressions \( (x - 5)(x + 3) \) and \( 2x^2 - x^2 - 2x - 20 + 5 \) are equivalent using the Distributive Property, we will expand Expression 1 and simplify Expression 2.
Step 1: Expand Expression 1 using the Distributive Property
Using the Distributive Property (specifically the FOIL method for binomials), we can expand \( (x - 5)(x + 3) \):
\[
(x - 5)(x + 3) = x \cdot x + x \cdot 3 - 5 \cdot x - 5 \cdot 3.
\]
Calculating each term:
- The first term: \(x \cdot x = x^2\).
- The outer term: \(x \cdot 3 = 3x\).
- The inner term: \(-5 \cdot x = -5x\).
- The last term: \(-5 \cdot 3 = -15\).
Now, combine the terms:
\[
x^2 + 3x - 5x - 15 = x^2 - 2x - 15.
\]
Thus, Expression 1 simplifies to \(x^2 - 2x - 15\).
Step 2: Simplify Expression 2
Next, we will simplify Expression 2:
\[
2x^2 - x^2 - 2x - 20 + 5.
\]
-
Combine the like terms \(2x^2 - x^2\):
\[
2x^2 - x^2 = x^2.
\]
-
Now, deal with the constants: \(-20 + 5\):
\[
-20 + 5 = -15.
\]
Putting it all together:
- The remaining terms are \(x^2 - 2x - 15\).
Therefore, Expression 2 simplifies to \(x^2 - 2x - 15\).
Conclusion
Now both expressions have been simplified to the same form:
Expression 1:
\((x - 5)(x + 3) = x^2 - 2x - 15\).
Expression 2:
\(2x^2 - x^2 - 2x - 20 + 5 = x^2 - 2x - 15\).
This shows that both expressions are equivalent, as they yield the same result, \(x^2 - 2x - 15\). Thus, we have demonstrated their equivalence using the Distributive Property.