Answer:
1) 2/5
2) -25
3) -8 14/15
4) 4/5
5) 7
Step-by-step explanation:
[tex]\begin{aligned}\textsf{1)} \quad \dfrac{-22+14}{2(-10)}& =\dfrac{-8}{-20}\\\\& = \dfrac{8}{20}\\\\& = \dfrac{8 \div 4}{20 \div 4}\\\\& = \dfrac{2}{5}\end{aligned}[/tex]
[tex]\begin{aligned}\textsf{2)} \quad -\dfrac{125}{5} &=-\dfrac{125 \div 5}{5 \div 5}\\\\& = -\dfrac{25}{1}\\\\& = -25\end{aligned}[/tex]
[tex]\begin{aligned}\textsf{3)} \quad -2 \frac{4}{5}-6 \frac{2}{15} & = -\dfrac{2 \times 5+4}{5}-\dfrac{6 \times 15+2}{15}\\\\& = -\dfrac{14}{5}-\dfrac{92}{15}\\\\& = -\dfrac{14 \times 3}{5 \times 3}-\dfrac{92}{15}\\\\& = -\dfrac{42}{15}-\dfrac{92}{15}\\\\& = \dfrac{-42-92}{15}\\\\& = \dfrac{-134}{15}\\\\& = -8 \dfrac{14}{15}\end{aligned}[/tex]
[tex]\begin{aligned}\textsf{4)} \quad 3 \frac{3}{5} \times \dfrac{2}{9} & = \dfrac{3 \times 5+3}{5} \times \dfrac{2}{9}\\\\& = \dfrac{18}{5}\times \dfrac{2}{9}\\\\& = \dfrac{18 \times 2}{5 \times 9}\\\\& = \dfrac{9 \times 2 \times 2}{5 \times 9}\\\\& = \dfrac{2 \times 2}{5}\\\\& = \dfrac{4}{5}\end{aligned}[/tex]
[tex]\begin{aligned}\textsf{5)} \quad-3x-21 & =-42\\-3x-21+21 & = -42+21\\-3x & = -21\\\dfrac{-3x}{-3} & = \dfrac{-21}{-3}\\x & = 7\end{aligned}[/tex]
