Question

Answer 1

bài 2:

M-N

\(=3xyz-3x^2+5xy-1-5x^2-xyz+5xy-3+y\)

\(=-8x^2+10xy+2xyz+y-4\)

N-M=-(M-N)

\(=-\left(-8x^2+10xy+2xyz+y-4\right)\)

\(=8x^2-10xy-2xyz-y+4\)

Bài 1:

a: A+B

\(=x^2y+x^3-xy^2+3+x^3+xy^2-xy-6\)

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

b: C+D

\(=\left(\dfrac{1}{3}a-\dfrac{1}{3}b\right)-a+2b+\left(\dfrac{1}{3}a+\dfrac{1}{3}b\right)-a-b\)

\(=\dfrac{2}{3}a-2a+b=-\dfrac{4}{3}a+b\)