Answer :

olumideolawoyin

Answer:

[tex]5.7 \times {10}^{ - 4}[/tex]

Step-by-step explanation:

[tex]8.5 \times {10}^{ - 4} - 2.8 \times {10}^{ - 4} = {10}^{ - 4}(8.5 - 2.8) [/tex]

[tex] = {10}^{ - 4} \times 5.7[/tex]

[tex] = 5.7 \times {10}^{ - 4} [/tex]