Simplify (25÷28)5×2−5
1/210
1/220
1/2(-15)
1/2(-5)
(25÷28)5×2−5
=(2528)5×2−5
∵aman= (a)m−n
⇒(25−8)5×2−5
=(2−3)5×2−5
∵am×an= (a)m+n
⇒2−15−5
=2−20
=1220
Simplify (25÷28)5 × 2−5.