a, `A = (8^4 × 4^6)/2^21`
`A = ((2^3)^4 × (2^2)^6)/2^21`
`A = (2^12 × 2^12)/2^21`
`A = 2^24/2^21`
`A = 2^3`
`A = 8`
b, `B = (2^15 × 9^4)/(6^6 × 8^3)`
`B = (2^15 × (3^2)^4)/(( 2 × 3 )^6 × (2^3)^3)`
`B = (2^15 × 3^8)/(2^6 × 3^6 × 2^9)`
`B = (2^15 × 3^8)/(2^15 × 3^6)`
`B = 3^2`
`B = 9`
c, `C = (2 . 6^9 - 2^5 . 18^4)/(2^2 . 6^8)`
`C = (2 . ( 2 . 3 )^9 - 2^5 . ( 2 . 3^2 )^4)/(2^2 . ( 2 . 3 )^8)`
`C = (2 . 2^9 . 3^9 - 2^5 . 2^4 . 3^8)/(2^2 . 2^8 . 3^8)`
`C = (2^9 . 3^8 ( 2 . 3 - 1 ))/(2^10 . 3^8)`
`C = 5/2`