①1/2(8x-6y)+3(y-x/3) ②3(2x-3y)-2(3x-2y) ③2(x²-3xy)-3(y²-2xy) ①1/2(8x-6y)+3(y-x/3)②3(2x-3y)-2(3x-2y)③2(x²-3xy)-3(y²-2xy)

问题描述:

①1/2(8x-6y)+3(y-x/3) ②3(2x-3y)-2(3x-2y) ③2(x²-3xy)-3(y²-2xy)
①1/2(8x-6y)+3(y-x/3)
②3(2x-3y)-2(3x-2y)
③2(x²-3xy)-3(y²-2xy)

①1/2(8x-6y)+3(y-x/3)
=4x-3y+3y-x
=3x

②3(2x-3y)-2(3x-2y)
=6x-9y-6x+4y
=-5y

③2(x²-3xy)-3(y²-2xy)
=2x²-6xy-3y²+6xy
=2x²-3y²

这样的问题也问?

①1/2(8x-6y)+3(y-x/3)=4x-3y+3y-x=(4x-x)+(-3y+3y)=3x②3(2x-3y)-2(3x-2y)=6x-9y-6x+4y=(6x-6x)+(-9y+4y)=-5y③2(x²-3xy)-3(y²-2xy)=2x²-6xy-3y²+6xy=2x²-3y²