Question

Просто помогите
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Answer 1

$\displaystyle 1)0,5x^2y*(-xy)=-0,5x^2yxy=-0,5x^3y^2\\\\ 2)-0,4x^4y^3*2,5x^2y^7=-1x^4^+^2y^3^+^7=-x^6y^1^0\\\\ 3)20a^3*(-5a)^2=20a^3*(5a)^2=20a^3*25a^2=500a^5\\\\ 4)(2^5*(2^3)^4):2^1^3=(2^5*2^1^2):2^1^3=2^1^7:2^1^3=2^4=16$