Solve (-7/13)*(39/49-13/21)

$$( - \frac { 7 } { 13 } ) \times ( \frac { 39 } { 49 } - \frac { 13 } { 21 } )$$

Evaluate

$$-\frac{2}{21}\approx -0.095238095$$

Solution Steps

Least common multiple of 49 and 21 is 147. Convert \frac{39}{49} and \frac{13}{21} to fractions with denominator 147.

$$-\frac{7}{13}\left(\frac{117}{147}-\frac{91}{147}\right)$$

Since \frac{117}{147} and \frac{91}{147} have the same denominator, subtract them by subtracting their numerators.

$$-\frac{7}{13}\times \frac{117-91}{147}$$

Subtract 91 from 117 to get 26.

$$-\frac{7}{13}\times \frac{26}{147}$$

Multiply -\frac{7}{13} times \frac{26}{147} by multiplying numerator times numerator and denominator times denominator.

$$\frac{-7\times 26}{13\times 147}$$

Do the multiplications in the fraction \frac{-7\times 26}{13\times 147}.

$$\frac{-182}{1911}$$

Reduce the fraction \frac{-182}{1911} to lowest terms by extracting and canceling out 91.

$$-\frac{2}{21}$$

Factor

$$-\frac{2}{21} = -0.09523809523809523$$