Tính: a, 5x^2 ( -x^2 + 2x -1) b, -3x(-2x +1) c, -1/2 xy( x^2 – xy +4) 02/08/2021 Bởi Kennedy Tính: a, 5x^2 ( -x^2 + 2x -1) b, -3x(-2x +1) c, -1/2 xy( x^2 – xy +4)
a) `5x²(-x²+2x-1)` `= -5x^4+10x³-5x²` b) `-3x(-2x+1)` `= 6x²-3x` c) `-1/2xy(x²-xy+4)` `= -1/2x³y+1/2x²y²-2xy` Bình luận
a) `5x^2(-x^2+2x-1)` `=5x^2.(-x^2)+5x^2.2x-5x^2` `=-5x^4+10x^3-5x^2` b) `-3x(-2x+1)` `=(-3x).(-2x)+(-3x)` `=6x^2-3x` c) `-1/2 xy(x^2-xy+4)` `=(-1/2 xy).x^2-1/2 xy.(-xy)-1/2 xy.4` `=-1/2 x^3y+1/2 x^2y^2-2xy` Bình luận
a) `5x²(-x²+2x-1)`
`= -5x^4+10x³-5x²`
b) `-3x(-2x+1)`
`= 6x²-3x`
c) `-1/2xy(x²-xy+4)`
`= -1/2x³y+1/2x²y²-2xy`
a) `5x^2(-x^2+2x-1)`
`=5x^2.(-x^2)+5x^2.2x-5x^2`
`=-5x^4+10x^3-5x^2`
b) `-3x(-2x+1)`
`=(-3x).(-2x)+(-3x)`
`=6x^2-3x`
c) `-1/2 xy(x^2-xy+4)`
`=(-1/2 xy).x^2-1/2 xy.(-xy)-1/2 xy.4`
`=-1/2 x^3y+1/2 x^2y^2-2xy`