Simplify the following expression: $\frac{\frac{2}{m} - 1}{\frac{m+7}{m-1} - \frac{3}{m}}$

AlgebraAlgebraic ExpressionsSimplificationFractionsRational ExpressionsFactorization
2025/4/25

1. Problem Description

Simplify the following expression:
2m1m+7m13m\frac{\frac{2}{m} - 1}{\frac{m+7}{m-1} - \frac{3}{m}}

2. Solution Steps

First, we simplify the numerator:
2m1=2mmm=2mm\frac{2}{m} - 1 = \frac{2}{m} - \frac{m}{m} = \frac{2-m}{m}
Next, we simplify the denominator:
m+7m13m=(m+7)m(m1)m3(m1)m(m1)=m2+7m3m+3m(m1)=m2+4m+3m(m1)\frac{m+7}{m-1} - \frac{3}{m} = \frac{(m+7)m}{(m-1)m} - \frac{3(m-1)}{m(m-1)} = \frac{m^2+7m - 3m + 3}{m(m-1)} = \frac{m^2 + 4m + 3}{m(m-1)}
We can factor the quadratic in the numerator of the denominator:
m2+4m+3=(m+1)(m+3)m^2 + 4m + 3 = (m+1)(m+3)
So the denominator becomes
(m+1)(m+3)m(m1)\frac{(m+1)(m+3)}{m(m-1)}
Now we have
2mm(m+1)(m+3)m(m1)=2mmm(m1)(m+1)(m+3)=(2m)(m1)(m+1)(m+3)\frac{\frac{2-m}{m}}{\frac{(m+1)(m+3)}{m(m-1)}} = \frac{2-m}{m} \cdot \frac{m(m-1)}{(m+1)(m+3)} = \frac{(2-m)(m-1)}{(m+1)(m+3)}
Thus, the expression simplifies to:
(2m)(m1)(m+1)(m+3)\frac{(2-m)(m-1)}{(m+1)(m+3)}

3. Final Answer

(2m)(m1)(m+1)(m+3)\frac{(2-m)(m-1)}{(m+1)(m+3)}

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