Question

Answer 1

Thay x=-1, y=-2 vào M ta có:
\(M=3x^2y+5xy-\dfrac{1}{2}xy^2\\ =3.\left(-1\right)^2.\left(-2\right)+5.\left(-1\right).\left(-2\right)-\dfrac{1}{2}.\left(-1\right).\left(-2\right)^2\\ =-6+10+2\\ =6\)

Answer 2

=6

Answer 3

Thay x = -1 ; y = -2 ta được 

\(A=3\left(-2\right)+10+\dfrac{1}{2}\left(-2\right)^2=-6+10+2=6\)