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The product of two consecutive negative integers is 20. Find the value of the lesser integer.​

1 Answer

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The consecutive negative integers are -5 and -4. Their product, -5 * -4, equals 20. Therefore, the value of the lesser integer is -5.

Let the consecutive negative integers be \( x \) and \( (x-1) \). According to the problem, their product is 20, so we can set up the equation:


\[ x \cdot (x-1) = 20 \]

Expanding and rearranging the equation gives us a quadratic equation:


\[ x^2 - x - 20 = 0 \]

Now, we can factor the quadratic equation:


\[ (x-5)(x+4) = 0 \]

This implies that either
\( x-5 = 0 \) or \( x+4 = 0 \). Solving these equations gives us two possible values for
\( x \): \( x = 5 \) or \( x = -4 \). Since we're dealing with negative integers, we discard the positive solution, leaving us with
\( x = -4 \).

Therefore, the consecutive negative integers are
\( -4 \) and
\( -5 \), and the lesser integer is
\( -5 \). So, the answer to the problem is that the value of the lesser integer is
\( -5 \).