Question

Tìm đa thức M, biết:

a. M + \(\left(5x^2-2xy\right)=6x^2+9xy-y^2\)

b. M + \(\left(3x^2y-2xy^3\right)=2x^2y-4xy^3\)

c. \(\left(\dfrac{1}{2}xy^2+x^2-x^2y\right)-M=-xy^2+x^2y+1\)

d. \(M-\left(x^3y^2-x^2y+xy\right)=2x^3y^2-\dfrac{3}{2}xy\)

Giúp mk nha, mk cần gấp lắm!

Answer 1

\(a.M+(5x^2-2xy)=6x^2+9xy-y^2 \)
\(M=(6x^2+9xy-y^2)-(5x^2-2xy)\)
\(M=6x^2+9xy-y^2-5x^2+2xy\)
\(M=(6x^2-5x^2)+(9xy+2xy)-y^2\)
\(M=x^2+11xy-y^2\)
Vậy \(M=x^2+11xy-y^2\)
\(b.M+(3x^2y-2xy^3)=2x^2y-4xy^3\)
\(M=(2x^2y-4xy^3)-(3x^2-2xy^3)\)
\(M= \) \(2x^2-4xy^3-3x^2+2xy^3\)
\(M=(2x^2-3x^2)+(-4xy^3+2xy^3)\)
\(M=-x^2-2xy^3\)
Vậy \(M=-x^2-2xy^3\)

Answer 2

Mình sẽ giúp bạn bài này a. M+(5x^2-2xy) = 6x^2+9xy-y^2 M = (6x^2+9xy-y^2) - (5x^2-2xy) = 6x^2+9xy-y^2-5x^2+2xy = (6x^2-5x^2)+(9xy+2xy)+(-y^2) = x^2+11xy-y^2 b. M + (3x^2y−2xy^3)=2x^2y−4xy^3 M = (2x^2y−4xy^3)-(3x^2y−2xy^3) = 2x^2y−4xy^3-3x^2y+2xy^3 = (2x^2y-3x^2y)+(−4xy^3+2xy^3) = -x^2y+(-2xy^3) c.(1/2xy^2+x^2−x^2y)−M=−xy^2+x^2y+1 M =(1/2xy^2+x^2−x^2y)-(−xy^2+x^2y+1) =1/2xy^2+x^2−x^2y-xy^2-x^2y-1 = (1/2xy^2-xy^2)+(x^2y-x^2y)+x^2-1 = -1/2xy^2+x^2-1 d. M−(x^3.y^2−x^2.y+xy)=2x^3.y^2−3/2xy M= (2x^3.y^2−3/2xy)+(x^3.y^2−x^2.y+xy) = 2x^3.y^2−3/2xy+x^3.y^2−x^2.y+xy = (2x^3.y^2+x^3.y^2)+(3/2xy+xy)-x^2.y = 3x^3.y^2+5/2xy-x^2.y

Answer 3

a) M + (5x\(^2\) - 2xy) = 6x\(^2\) + 9xy - y\(^2\)

=> M = (6x\(^2\) + 9xy - y\(^2\)) - (5x\(^2\) - 2xy)

M = 6x\(^2\) + 9xy - y\(^2\) - 5x\(^2\) + 2xy

M = (6x\(^2\) - 5x\(^2\)) + (9xy + 2xy) - y\(^2\)

M = 1x\(^2\) + 11xy - y\(^2\)

Answer 4

b) M + (3x\(^2\)y - 2xy\(^3\)) = 2x\(^2\)y - 4xy\(^3\)

=> M = (2x\(^2\)y - 4xy\(^3\)) - (3x\(^2\)y - 2xy\(^3\))

M = 2x\(^2\)y - 4xy\(^3\) - 3x\(^2\)y + 2xy\(^3\)

M = (2x\(^2\)y - 3x\(^2\)y) + (-4xy\(^3\) + 2xy\(^3\))

M = -1x\(^2\)y - 2xy\(^3\)

Vậy đa thức M = -1x\(^2\)y - 2xy\(^3\)

Answer 5

d) M - (x\(^3\)y\(^2\) - x\(^2\)y + xy) = 2x\(^3\)y\(^2\) - \(\dfrac{3}{2}\)xy

=> M = (2x\(^3\)y\(^2\) - \(\dfrac{3}{2}\)xy) + (x\(^3\)y\(^2\) - x\(^2\)y + xy)

M = 2x\(^3\)y\(^2\) - \(\dfrac{3}{2}\)xy + x\(^3\)y\(^2\) - x\(^2\)y + xy

M = (2x\(^3\) y\(^2\) + x\(^3\)y\(^2\)) + (\(\dfrac{-3}{2}\)xy + xy) - x\(^2\)y

M = 3x\(^3\)y\(^2\) - \(\dfrac{1}{2}\)xy - x\(^2\)y

Answer 6

c) (\(\dfrac{1}{2}\)xy\(^2\) + x\(^2\) - x\(^2\)y) - M = -xy\(^2\) + x\(^2\)y + 1

=> M = (\(\dfrac{1}{2}\)xy\(^2\) + x\(^2\) - x\(^2\)y) - (-xy\(^2\) + x\(^2\)y + 1)

M = \(\dfrac{1}{2}\)xy\(^2\) + x\(^2\) - x\(^2\)y + xy\(^2\) - x\(^2\)y - 1

M = (\(\dfrac{1}{2}\)xy\(^2\) + xy\(^2\)) + (-x\(^2\)y - x\(^2\)y) + x\(^2\) - 1

M = \(\dfrac{3}{2}\)xy\(^2\) - 2x\(^2\)y + x\(^2\) - 1