Expanding the Expression (x+5)(x-7)
In mathematics, expanding an expression means to simplify it by multiplying out any brackets. Here's how to expand the expression (x+5)(x-7):
Using the FOIL Method
The FOIL method is a common technique for expanding expressions like this. FOIL stands for:
- First: Multiply the first terms of each bracket.
- Outer: Multiply the outer terms of the brackets.
- Inner: Multiply the inner terms of the brackets.
- Last: Multiply the last terms of each bracket.
Let's apply this to our expression:
- First: x * x = x²
- Outer: x * -7 = -7x
- Inner: 5 * x = 5x
- Last: 5 * -7 = -35
Now, combine the terms:
x² - 7x + 5x - 35
Finally, simplify by combining like terms:
x² - 2x - 35
Alternative Approach: Distributive Property
You can also use the distributive property to expand the expression. The distributive property states that a(b + c) = ab + ac.
Here's how it applies to our problem:
-
Distribute the first term (x) from the first bracket to both terms in the second bracket: x(x-7) = x² - 7x
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Distribute the second term (5) from the first bracket to both terms in the second bracket: 5(x-7) = 5x - 35
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Combine the results: x² - 7x + 5x - 35
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Simplify: x² - 2x - 35
Both methods lead to the same answer: x² - 2x - 35.