Toán (x+1)^3+(x-2)^3 1-y^3+6xy^2-12x^2y+8x^3 2004^2-16 giúp em với ạ 11/07/2021 By Alexandra (x+1)^3+(x-2)^3 1-y^3+6xy^2-12x^2y+8x^3 2004^2-16 giúp em với ạ
`(x+1)³+(x-2)³` `=[(x+1)+(x-2)][(x+1)²-(x+1)(x-2)+(x-2)²]` `=(x+1+x-2)[x²+2x+1-(x²-2x+x-2)+x²-4x+4]` `=(2x-1)(x²+2x+1-x²+2x-x+2+x²-4x+4)` `=(2x-1)(x²-x+7)` `1-y³+6xy²-12x²y+8x³` `=1-(y³-6xy²+12x²y-8x³)` `=1-[y³-3.y².2x+3.y.(4x)²-(2x)³]` `=1-(y-2x)³` `=(1-y+2x)[1²+1(y-2x)+(y-2x)²]` `=(1-y+2x)(1+y-2x+y²-4xy+4x²)` `2004²-16` `=2004²-4²` `=(2004+4)(2004-4)` `=2008.2000` `=4016000` Trả lời
`a) (x+1)^3 + (x-2)^3` ` = [ (x+1) + (x-2) ] . [ (x+1)^2 – (x+1).(x-2) + (x-2)^2]` ` = (x+1+x-2) . [ (x^2 +2x+1) – (x^2 – 2x + x -2) + (x^2 – 4x+4)]` ` = (2x – 1) . (x^2 + 2x + 1 – x^2 + 2x – x + 2 + x^2 – 4x + 4)` ` = (2x-1) . (x^2 -x+7)` `b) 1 – y^3 + 6xy^2 – 12x^2y + 8x^3` ` = 1 – (y^3 – 6xy^2 + 12x^2y – 8x^3)` ` = 1 – ( y – 2x)^3` ` = [ (1 – ( y-2x)] . [ 1 + y – 2x + (2x-y)^2]` ` = (1 – y + 2x) . (1 + y – 2x + y^2 – 4xy + 4x^2)` `c) 2004^2 – 16` ` = 2004^2 – 4^2` ` =(2004 – 4) . (2004+ 4)` ` = 2000 . 2008` Trả lời
`(x+1)³+(x-2)³`
`=[(x+1)+(x-2)][(x+1)²-(x+1)(x-2)+(x-2)²]`
`=(x+1+x-2)[x²+2x+1-(x²-2x+x-2)+x²-4x+4]`
`=(2x-1)(x²+2x+1-x²+2x-x+2+x²-4x+4)`
`=(2x-1)(x²-x+7)`
`1-y³+6xy²-12x²y+8x³`
`=1-(y³-6xy²+12x²y-8x³)`
`=1-[y³-3.y².2x+3.y.(4x)²-(2x)³]`
`=1-(y-2x)³`
`=(1-y+2x)[1²+1(y-2x)+(y-2x)²]`
`=(1-y+2x)(1+y-2x+y²-4xy+4x²)`
`2004²-16`
`=2004²-4²`
`=(2004+4)(2004-4)`
`=2008.2000`
`=4016000`
`a) (x+1)^3 + (x-2)^3`
` = [ (x+1) + (x-2) ] . [ (x+1)^2 – (x+1).(x-2) + (x-2)^2]`
` = (x+1+x-2) . [ (x^2 +2x+1) – (x^2 – 2x + x -2) + (x^2 – 4x+4)]`
` = (2x – 1) . (x^2 + 2x + 1 – x^2 + 2x – x + 2 + x^2 – 4x + 4)`
` = (2x-1) . (x^2 -x+7)`
`b) 1 – y^3 + 6xy^2 – 12x^2y + 8x^3`
` = 1 – (y^3 – 6xy^2 + 12x^2y – 8x^3)`
` = 1 – ( y – 2x)^3`
` = [ (1 – ( y-2x)] . [ 1 + y – 2x + (2x-y)^2]`
` = (1 – y + 2x) . (1 + y – 2x + y^2 – 4xy + 4x^2)`
`c) 2004^2 – 16`
` = 2004^2 – 4^2`
` =(2004 – 4) . (2004+ 4)`
` = 2000 . 2008`