Toán phân tích thành nhân tử 1. x² + 2xy + y² – 9 2. x² – y² + xy + x² 25/11/2021 By Emery phân tích thành nhân tử 1. x² + 2xy + y² – 9 2. x² – y² + xy + x²
`1. x² + 2xy + y² – 9 ` `= ( x² + 2xy + y²) – 9` `= (x+y)² – 9 ` `= (x+y)² – 3²` `= (x+y-3)(x+y+3)` `2. x² – y² + xy + x²` `= (x²-y²)+(xy + x²)` `= (x+y)(x-y)+x(x+y)` `= (x+y)(x-y+x)` `= -y(x+y)` Trả lời
1, x² + 2xy + y² – 9 (x² + 2xy + y²) – 9 ( x + y )² – 3² ( x + y + 3 ) ( x + y – 3 ) 2 x² – y² + xy + x² ( x² – y²) + (xy + x²) (x + y)(x – y ) – x( y + x) (x + y)(x-y-x) -y(x+y) Trả lời
`1. x² + 2xy + y² – 9 `
`= ( x² + 2xy + y²) – 9`
`= (x+y)² – 9 `
`= (x+y)² – 3²`
`= (x+y-3)(x+y+3)`
`2. x² – y² + xy + x²`
`= (x²-y²)+(xy + x²)`
`= (x+y)(x-y)+x(x+y)`
`= (x+y)(x-y+x)`
`= -y(x+y)`
1, x² + 2xy + y² – 9
(x² + 2xy + y²) – 9
( x + y )² – 3²
( x + y + 3 ) ( x + y – 3 )
2 x² – y² + xy + x²
( x² – y²) + (xy + x²)
(x + y)(x – y ) – x( y + x)
(x + y)(x-y-x)
-y(x+y)