giúp em với mn ơi
Thu gọn :
a, 2xy ² . ( -3 x ²y ) ² b, ( -2x ² ) ² . ( 3xy ² ) ³ . 5x ²
c, (1/3 xy ²z) . (-3/2 x ²y ) ² . 2yz ² d, ( 3x ² ) ³ . ( -1/9 y ³ ) . ( -5 xyz ) ³
e, (-2 1/3 xy ) . ( 1 1/4 x ²y ) . (-5/6 xy ) ²
Đáp án:
$a) 18x^5y^4\\
b) 540x^9y^6\\
c) \dfrac{3}{2}x^5y^5z^3\\
d)
375x^9y^6z^3\\
e)
\dfrac{-875}{432}x^5y^4$
Giải thích các bước giải:
$a) 2xy^2.(-3x^2y)^2=2xy^2.9x^4y^2=18x^5y^4\\
b) (-2x^2)^2.(3xy^2)^3.5x^2=4x^4.27x^3y^6.5x^2=540x^9y^6\\
c) \left ( \dfrac{1}{3}xy^2z \right ).\left ( \dfrac{-3}{2}x^2y\right )^2.2yz^2\\
=\dfrac{1}{3}xy^2z.\dfrac{9}{4}x^4y^2.2yz^2\\
=\dfrac{3}{2}x^5y^5z^3\\
d)
(3x^2)^3.\left ( -\dfrac{1}{9}y^3 \right ).(-5xyz)^3\\
=27x^6.\dfrac{-1}{9}y^3.(-125)x^3y^3z^3\\
=27.\dfrac{-1}{9}.(-125).x^9y^6z^3\\
=375x^9y^6z^3\\
e)
\left ( -2\dfrac{1}{3}xy \right ).\left ( 1\dfrac{1}{4}x^2y \right ).\left ( \dfrac{-5}{6}xy \right )^2\\
=\dfrac{-7}{3}xy.\dfrac{5}{4}x^2y.\left (\dfrac{-5}{6} \right )^2x^2y^2\\
=\dfrac{-7}{3}.\dfrac{5}{4}.\dfrac{25}{36}x^5y^4\\
=\dfrac{-875}{432}x^5y^4$