To factor the expression \( 8x^2 + 16x - 10 \) completely, we will start by factoring out the greatest common factor (GCF) from the expression.
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Identify the GCF: The coefficients are 8, 16, and -10. The GCF of these numbers is 2.
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Factor out the GCF: \[ 8x^2 + 16x - 10 = 2(4x^2 + 8x - 5) \]
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Factor the quadratic \( 4x^2 + 8x - 5 \): Now, we will factor \( 4x^2 + 8x - 5 \) by finding two numbers that multiply to \( (4)(-5) = -20 \) and add to \( 8 \).
The numbers that work are \( 10 \) and \( -2 \).
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Re-write the middle term: \[ 4x^2 + 10x - 2x - 5 \]
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Group the terms: \[ (4x^2 + 10x) + (-2x - 5) \]
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Factor by grouping: \[ 2x(2x + 5) - 1(2x + 5) \] \[ = (2x + 5)(2x - 1) \]
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Combine everything: So, we have \[ 8x^2 + 16x - 10 = 2(2x + 5)(2x - 1) \]
Now, we can determine if any of the provided options is a factor by checking each expression:
- \( x - 10 \)
- \( 2x + 3 \)
- \( 4x - 1 \)
- \( 2x + 5 \)
Since we factored the original expression into \( 2(2x + 5)(2x - 1) \), it's clear that:
- \( 2x + 5 \) is indeed a factor of \( 8x^2 + 16x - 10 \).
So the answer is:
\[ \text{The expression that is a factor is } 2x + 5. \]