`= (17 xx 21 xx 7 xx 9)/(17 xx 21 xx 35 xx 45)`
`= ( 7 xx 9)/(7 xx 5 xx 9 xx 5)`
`= 1/25`
17/35 x 21/45 x 7/17 x 9/21 = ( 17/35 x 7/17 ) x ( 21/45 x 9/21 )
= 1/5 x 1/5
= 1/25
\(\dfrac{17}{35}\times\dfrac{21}{45}\times\dfrac{7}{17}\times\dfrac{9}{21}=\dfrac{17}{75}\times\dfrac{7}{17}\times\dfrac{9}{21}=\dfrac{7}{75}\times\dfrac{9}{21}=\dfrac{1}{25}\)
17/17 x 21/21 x 7/35 x 9/45
= 7 x 9/45 x 35
=1/25