Expanding the Expression (x-7)(x+4)
This article will explore the expansion of the expression (x-7)(x+4), using the distributive property or the FOIL method.
Expanding using the Distributive Property
The distributive property states that a(b+c) = ab + ac. We can use this to expand our expression:
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Treat (x-7) as a single term:
(x-7)(x+4) = (x-7) * x + (x-7) * 4
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Distribute:
(x-7) * x + (x-7) * 4 = x² - 7x + 4x - 28
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Combine like terms:
x² - 7x + 4x - 28 = x² - 3x - 28
Expanding using the FOIL Method
FOIL is an acronym that stands for First, Outer, Inner, Last. It helps us remember the steps involved in multiplying two binomials:
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Multiply the First terms: x * x = x²
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Multiply the Outer terms: x * 4 = 4x
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Multiply the Inner terms: -7 * x = -7x
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Multiply the Last terms: -7 * 4 = -28
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Combine like terms: x² + 4x - 7x - 28 = x² - 3x - 28
Conclusion
Both methods, the distributive property and FOIL, lead to the same result: x² - 3x - 28. The choice of method is a matter of personal preference. The key is to understand how to apply the distributive property and to be able to combine like terms.