Step-by-step explanation:
[tex] \\ 20. \: \: ( \frac{ - 3}{4} )(4\frac{1}{6} )[/tex]
[tex] \\ = \frac{ - 3}{4} \times \frac{25}{6} [/tex]
[tex] \\ = \frac{ - 25}{8} [/tex]
[tex] \\ = - 3.125[/tex]
[tex] \\ 21. \: \: ( - 3\frac{7}{8} )( - 5\frac{3}{4} )[/tex]
[tex] \\ = \frac{ - 31}{8} \times \frac{ - 23}{4} [/tex]
[tex] \\ = \frac{713}{32} [/tex]
[tex] \\ = 22.28125[/tex]
