Expanding (x+1)(x-4)
The expression (x+1)(x-4) is a product of two binomials. To expand this expression, we can use the distributive property or the FOIL method.
Using the Distributive Property
The distributive property states that a(b+c) = ab + ac. We can apply this property twice to expand the expression:
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Distribute (x+1) over (x-4): (x+1)(x-4) = x(x-4) + 1(x-4)
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Distribute x and 1: x(x-4) + 1(x-4) = x² - 4x + x - 4
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Combine like terms: x² - 4x + x - 4 = x² - 3x - 4
Using the FOIL Method
FOIL stands for First, Outer, Inner, Last. This method provides a systematic way to multiply binomials.
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First: Multiply the first terms of each binomial: x * x = x²
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Outer: Multiply the outer terms of the binomials: x * -4 = -4x
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Inner: Multiply the inner terms of the binomials: 1 * x = x
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Last: Multiply the last terms of each binomial: 1 * -4 = -4
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Combine like terms: x² - 4x + x - 4 = x² - 3x - 4
Conclusion
Both methods lead to the same result: (x+1)(x-4) = x² - 3x - 4. This expanded form represents a quadratic expression.