`1)`
`(2x^2y) . (-3xyz^2) . (5x^2y^2z^2)^2`
`= (2x^2y) . (-3xyz^2) . (25x^4y^4z^4)`
` = [ 2 . (-3) . 25] . (x^2 . x . x^4) . (y . y . y^4) . (z^2 . z^4)`
` = -150 x^7 y^6 z^6`
`2)`
`(3x^3y^2z)^2 . (xyz^2) . (-7xy^2 z)^3`
` = (9x^6y^4z^2) . (xyz^2) . (-343 x^3 y^6 z^3)`
` = [ 9 . (-343)] . (x^6 . x . x^3) . (y^4 . y . y^6) . (z^2 . z^2 . z^3)`
` = -3087 x^10 y^11 z^7`
`3)`
`(-5xyz^2) . (-3x^3) . (-xy^5)^3`
`= (-5xyz^2)(-3x^3) . (-x^3 y^15)`
` = [ (-5) . (-3) . (-1)] . (x . x^3 . x^3) . (y . y^15) . z^2`
` = -15 x^7 y^16 z^2`
`4)`
`(-1/2 xy^2)^3 . (3/5 x^3y)^4 . ( (-10)/21 xy )^2`
` = (-1/8 x^3 y^6) . (81/625 x^12 y^4) . (100/441 x^2 y^2)`
` = (-1/8 . 81/625 . 100/441) . (x^3 . x^12 . x^2) . (y^6 . y^4 . y^2)`
` = -9/2450 x^17 y^12`
