Câu 1: C
Tại x = -2; y=3 , ta có:
$A^{}$ = $5x^{}$ - $5y^{}$ + $1^{}$ = $5.(-2)^{}$ - $5.3^{}$ + $1^{}$ = $-10^{}$ - $15^{}$ + $1^{}$ = $-24^{}$
Câu 2: A
Câu 3: D
Nhóm 1: $4xy^{2}$$t^{}$
Nhóm 2: $-x^{2}$$y^{};$ $3x^{2}$$y^{};$ $\cfrac{-1}{2x^{2}y^{}}$
Nhóm 3: $2xy^{2}$
Nhóm 4: $\cfrac{1}{2}$$xy^{};$ $-\sqrt[]{2}$$xy^{}$
Câu 4: C
Cho f(x) = 1
Ta có: f(x) = $3x^{5}$ - $3x^{4}$ + $5x^{3}$ - $x^{2}$ + $5x^{}$ + $2_{}$ = $3.1^{5}$ - $3.1^{2}$ + $5.1^{3}$ - $1^{2}$ + $5.1^{}$ + $2_{}$ = $3_{}$ - $3_{}$ + $5_{}$ - $1_{}$ + $5_{}$ + $2_{}$ = $11_{}$
Câu 5: D
$Q(x)^{}$ - $N(x)^{}$ = $-2y^{4}$ + $x^{2}$$y^{}$ + $xy^{}$
⇒$N(x)^{}$ = $Q(x)^{}$ - $-2y^{4}$ + $x^{2}$$y^{}$ + $xy^{}$
= $(3xy^{2}$ - $2xy^{}$ + $x^{2}$$y^{}$ - $2y^{4})$ - $(-2y^{4}$ + $x^{2}$$y^{}$ + $xy^{})$
= $3xy^{2}$ - $2xy^{}$ + $x^{2}$$y^{}$ - $2y^{4}$ + $2y^{4}$ - $x^{2}$$y^{}$ - $xy^{}$
= $3xy^{2}$ - $3xy^{}$
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