Step-by-step explanation:
Multiply:
[tex] \frac{ - 5}{7} \times \frac{ - 21}{55} = \frac{105}{385} [/tex]
Divide each side by 35:
[tex] \frac{105 \div 35}{385 \div 35} = \frac{3}{11} [/tex]
Your simplified product is 3/11.