Question

help me =((

Answer 1

Bài `1` 

Áp dụng HĐT `1;2;3;4;5` là ra nha.

Bài `2`

`a, x^2 +6x+9`

`= x^2 +2.3.x+3^2`

`=(x+3)^2`

`b, 9x^2 -6x+1`

`=(3x)^2 - 2.3x.1+1^2`

`= (3x-1)^2`

`c, x^2y^2 +xy+1/4`

`=(xy)^2+2.1/2.xy +(1/2)^2`

`=(xy+1/2)^2`

`d, (x-y)^2 +6(x-y) +9`

`=(x-y)^2 + 2.3.(x-y)+3^2`

`=(x-y+3)^2`

`e, x^2 +8x+16`

`=x^2 +2.4.x+4^2`

`=(x+4)^2`

`f,9x^2 -24x+16`

`=(3x)^2 -2.3x.4+4^2`

`=(3x-4)^2`

`g, x^2-3x+9/4`

`=x^2 -2.3/2.x+(3/2)^2`

`=(x-3/2)^2`

`h, 4x^2y^4-4xy^3+y^2`

`=(2xy^2)^2 - 2.2xy^2.y +y^2`

`=(2xy^2-y)^2`

`i, (x-2y)^2 -4(x-2y)+4`

`= (x-2y)^2 -2.2.(x-2y)+2^2`

`=(x-2y -2)^2`

`k,(x+3y)^2 -12xy`

`=(x-3y)^2`

`i, (4x+7)^2`

`= (4x)^2 + 2.4x.7+7^2`

`=16x^2 + 56x+49`

`m,(6x-1/3y)^2`

`= (6x)^2 - 2.6x.1/3 +(1/3y)^2`

`= 36x^2 - 4x+1/9y^2`