Question

please help me to solve this sum^_^
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Answer 1

1.

5/7 × -14/25 + 15/8

= -2/5 + 15/8

= (-16+75)/40

= 59/40

2.

(3^-5 × 10^-5 ×5^3) ÷ (5^-7 × 6^-5 × 5^5)

= { 1/(3^5 × 10^5) }×5^3 ÷ {1/ (5^7 × 6^5 ) }× 5^5

= 5^(3+5) × (5^7 × 6^5 ) / (3^5 × 10^5 )

= 5^8 × (5^7 × 3^5 × 2^5) / (3^5 × 5^5 × 2^5)

= 5^(8+7) / 5^5

= 5^ (15 - 5)

= 5^10