Solve (-5)*81/2+(-7)div(-21/2)

$$( - 5 ) \times 8 \frac { 1 } { 2 } + ( - 7 ) \div ( - 2 \frac { 1 } { 2 } )$$

Evaluate

$$-\frac{397}{10}=-39.7$$

Solution Steps

Multiply 8 and 2 to get 16.

$$-5\times \frac{16+1}{2}+\frac{-7}{-\frac{2\times 2+1}{2}}$$

Add 16 and 1 to get 17.

$$-5\times \frac{17}{2}+\frac{-7}{-\frac{2\times 2+1}{2}}$$

Express -5\times \frac{17}{2} as a single fraction.

$$\frac{-5\times 17}{2}+\frac{-7}{-\frac{2\times 2+1}{2}}$$

Multiply -5 and 17 to get -85.

$$\frac{-85}{2}+\frac{-7}{-\frac{2\times 2+1}{2}}$$

Fraction \frac{-85}{2} can be rewritten as -\frac{85}{2} by extracting the negative sign.

$$-\frac{85}{2}+\frac{-7}{-\frac{2\times 2+1}{2}}$$

Multiply 2 and 2 to get 4.

$$-\frac{85}{2}+\frac{-7}{-\frac{4+1}{2}}$$

Add 4 and 1 to get 5.

$$-\frac{85}{2}+\frac{-7}{-\frac{5}{2}}$$

Divide -7 by -\frac{5}{2} by multiplying -7 by the reciprocal of -\frac{5}{2}.

$$-\frac{85}{2}-7\left(-\frac{2}{5}\right)$$

Express -7\left(-\frac{2}{5}\right) as a single fraction.

$$-\frac{85}{2}+\frac{-7\left(-2\right)}{5}$$

Multiply -7 and -2 to get 14.

$$-\frac{85}{2}+\frac{14}{5}$$

Least common multiple of 2 and 5 is 10. Convert -\frac{85}{2} and \frac{14}{5} to fractions with denominator 10.

$$-\frac{425}{10}+\frac{28}{10}$$

Since -\frac{425}{10} and \frac{28}{10} have the same denominator, add them by adding their numerators.

$$\frac{-425+28}{10}$$

Add -425 and 28 to get -397.

$$-\frac{397}{10}$$

Factor

$$-\frac{397}{10} = -39\frac{7}{10} = -39.7$$