Thôi đặt câu khác vậy phân tích giúp mik với a, x^3 - 2x^2 + x b,2x^2 + 4x + 2 - 2y^2 c, 2xy - x^2 - y^2 + 16
2 câu trả lời
Đáp án:
`a) x ( x - 1 )^2 `
`b) 2 ( x + 1 - y ) ( x + 1 + y ) `
`c) ( 4 - x + y ) ( 4 + x - y ) `
Giải thích các bước giải:
`a) x^3 - 2x^2 + x `
`= x ( x^2 -2x + 1 ) `
`= x ( x - 1 )^2 `
`b) 2x^2 + 4 + 2 - 2y^2`
`= 2 ( x^2 + 2x + 1 - y^2 ) `
`= 2 [ ( x^2 + 2x + 1 ) - y^2 ] `
`= 2 [ ( x + 1 )^2 - y^2 ] `
`= 2 [ ( x + 1 ) - y ] [ ( x + 1 ) + y ] `
`= 2 ( x + 1 - y ) ( x + 1 + y ) `
`c ) 2xy - x^2 - y^2 + 16 `
`= 16 - ( x^2 + 2x + 1 - y^2 ) `
`= 16 - ( x^2 - 2xy + y^2 ) `
`= 4^2 - ( x - y )^2 `
`= [ 4 - ( x - y ) ] [ 4 + ( x - y ) ] `
`= ( 4 - x + y ) ( 4 + x - y ) `
Đáp án:
$a) x^3-2x^2+x$
$= x.x^2-x.2x+x.1$
$= x.(x^2-2x+1)$
$= x.(x-1)62$
$b) 2x^2+4x+2-2y^2$
$= 2.(x^2+2x+1-y²)$
$= 2.[(x^2+2x+1)-y^2]$
$= 2.[(x+1)²-y^2]$
$= 2.(x+1-y).(x+1+y)$
$c) 2xy-x²-y²+16$
$= 16-(x²-2xy+y²)$
$= 4²-(x-y)²$
$= (4-x+y).(4+x-y)$