giúp mình vs ạ, mình cảm ơn trước!
Phân tích đa thức sau thành nhân tử:
a) $4x^{2}$ -12x + 9 b) $4x^{2}$ +4x + 1 c) 1 + 12x + $36x^{2}$
d) $9x^{2}$ – 24xy + 16$y^{2}$ e) x^2/4 + 2xy + $4y^{2}$
f) $-x^{2}$ + 10x – 25 g) $-16a^{4}$ $b^{6}$ – 24 $a^{5}$$b^{5}$ – 9 $a^{6}$$b^{4}$
h) 25x^2 – 20xy + 4y^2 i) 25x^4 – 10x^2y +y^2
Nhanh hộ mình, cảm ơn nhiều!
Đáp án:
Giải thích các bước giải:
`4x^2 -12x+9`
`=(2x)^2 -2.2x.3+3^2`
`=(2x-3)^2`
b) `4x^2+4x + 1`
`=(2x)^2 -2.2x.1+1^2`
`=(2x-1)^2`
c) `1 + 12x +36x^2`
`=1^2 +2.1.6x+(6x)^2`
`=(1+6x)^2`
d) `9x^2+24xy+16y^2`
`=(3x)^2+2.3x.4y+(4y)^2`
`=(3x+4y)^2`
e) `x^2/4 + 2xy + 4y^2`
`=(x/2)^2+2.x/2.2y+(2y)^2`
`= (x/2 + 2y)^2`
f) `−x^2+10x−25`
`=−(x^2−10x+25)`
`=−(x−5)^2`
g) `−16a^4 b^6 – 24 a^5b^5 – 9 a^6b^4`
`=a^4b^4 (-16b^2 ‐24ab -9a^2 )`
`=a^4b^4 – (16b^2 +24ab +9a^2 )`
`=a^4b^4 – (4b +3a)^2`
`=(a^2b^2)^2 – (4b +3a)^2`
`=(a^2b^2 – 4b – 3a )(a^2b^2 +4b +3a )`
h)` 25x^2 – 20xy + 4y^2`
`= (5x)^2 – 2.5x.2y + (2y)^2`
`= (5x – 2y)^2`
i) `25x^4 – 10x^2y +y^2`
`= (5x^2)^2 – 2.5x^2.y + y^2`
`= (5x^2 – y)^2`
a) `4x^2-12x+9 = (2x)^2 – 2.2x.3 + 3^2= (2x-3)^2`
b) `4x^2+4x+1 = (2x)^2+2.2x.1 +1^2 = (2x+1)^2`
c) `1+12x+36x^2 = 1^2+2.1.6x + (6x)^2 = (1+6x)^2`
d) `9x^2-24xy+16y^2 = (3x)^2 – 2.3x.4 + (4y)^2 = (3x+4y)^2`
e) `(x^2)/4 + 2xy + 4y^2 = (x/2)^2 + 2. x/2 . 2y + (2y)^2 = (x/2 +2y)^2`
f) `-x^2+10x-25 =-(x^2 – 2.x.5 + 5^2) = -(x-5)^2`
g) `-16a^4 b^6 – 24a^5 b^5 – 9a^6 b^4`
`= -[ (4a^2 b^3)^2 + 2. 4a^2 b^3 . 3a^3 b^2 + (3a^3 b^2)^2] `
`= -(4a^2b^3 + 3a^3b^2)^2`
h) `25x^2-20xy+y^2 = (5x)^2 – 2.5x.y + y^2 = (5x-y)^2`
i) `25x^4-10x^2y+y^2 = (5x^2)^2 – 2.5x^2 .y + y^2 = (5x^2-y)^2`