Question

Cho A= -5x^3y-14xy^2-9-12x^2y Tính giá trị tại x= -1 y =-1/2 Giải giúp mình với=))

Answer 1

Thay \(x=-1;y=-\dfrac{1}{2}\) vào \(A=-5x^3y-14xy^2-9-12x^2y\)

\(\Rightarrow A=-5.\left(-1\right)^3.\left(-\dfrac{1}{2}\right)-14.\left(-1\right).\left(-\dfrac{1}{2}\right)^2-9-12.\left(-1\right)^2.\left(-\dfrac{1}{2}\right)\)

\(\Rightarrow A=-\dfrac{5}{2}+\dfrac{7}{2}-9+6\)

\(\Rightarrow A=-2\)

Answer 2

\(A=-5x^3y-14xy^2-9-12x^2y\)

Thay \(x=-1;y=-\dfrac{1}{2}\) vào A

\(A=-5.\left(-1\right)^3.\left(-\dfrac{1}{2}\right)-14.\left(-1\right).\left(-\dfrac{1}{2}\right)^2-9-12.\left(-1\right)^2.\left(-\dfrac{1}{2}\right)=-2\)

Vậy với \(x=-1;y=-\dfrac{1}{2}\) thì A \(=-2\)