Which expression can be multiplied by the numerator and denominator to help evaluate the limit? limit x to negative 1 of the fraction with numerator square root of x minus 1 end root plus 1 and denominator x plus 1

To simplify a numerator containing a square root, multiply by its conjugate. The conjugate of √(x − 1) + 1 is √(x − 1) − 1, so choice B is the expression to use. Their product is (x − 1) − 1², which removes the square root.

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