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\(5x^2y^3-25x^2y^2+10x^2y^4=5x^2y^2\left(y-5+2y^2\right)\)
\(12a^4-24a^2b^2-6ab=6a\left(2a^3-4ab^2-3b\right)\)
mk chỉnh đề
\(-25x^6-y^8+10x^3y^4=-\left(5x^3-y^4\right)^2\)
\(25-\left(3-x\right)^2=\left(5-3+x\right)\left(5+3-x\right)=\left(2+x\right)\left(8-x\right)\)
x9 + 1
= (x3)3 + 13
= (x3 + 1)(x6 - x3 + 1)
= (x + 1)(x2 - x + 1)(x6 - x3 +1)
8a3 - 12a2 + 6a - 1
= (2a)3 - 3(2a)21 + 3 . 2a . 12 - 1
= (2a - 1)3
27a3 - 54a2b + 36ab2 - 8b3
= (3a)3 - 3(3a)22b + 3 . 3a . (2b)2 - (2b)3
= (3a - 2b)3
Bài 1 :
Ta có : \(VP=\left(a+b\right)^4=\left(a+b\right)\left(a+b\right)^3\)
\(=\left(a+b\right)\left(a^3+3a^2b+3ab^2+b^3\right)=a^4+4a^3b+6a^2b^2+4ab^3+b^4\)
=> HĐT ko đc CM
Bài 2 :
a, \(\left(x-2\right)\left(x^2+2x+4\right)-\left(x-1\right)+7\)
\(=x^3+2x^2+4x-2x^2-4x-8-x+1+7=x^3-x=x\left(x^2-1\right)\)
Sửa đề : b, \(8\left(x-1\right)\left(x^2+x+1\right)-\left(2x-1\right)\left(4x^2+2x+1\right)\)
\(=8\left(x^3-1\right)-8x^3+1=8x^3-8-8x^3+1=-7\)
Xin phép chủ nahf cho mjnh sửa đề:D
\(\left(a+b\right)^4=a^4+4a^3b+6a^2b^2+4ab^3+b^4\)
a,\(\left(a+b\right)^4\)
\(=\left[\left(a+b\right)^2\right]^2\)
\(=\left(a^2+2ab+b^2\right)^2\)
\(=\left[\left(a^2+2ab\right)+b^2\right]^2\)
\(=\left(a^2+2ab\right)^2+2\left(a^2+2ab\right)b^2+b^4\)
\(=a^4+4a^3b+4a^2b^2+2a^2b^2+4ab^3+b^4\)
\(=a^4+4a^3b+6a^2b^2+4ab^3+b^4\)
Bài 2:
a,\(\left(x-2\right)\left(x^2+2x+4\right)-\left(x-1\right)+7\)
\(=\left(x^3-8\right)-\left(x-1\right)+7\)
b,\(8\left(x-1\right)\left(x^2+x+1\right)-\left(2x-1\right)\left(4x^2+2x-1\right)\)
\(=8\left(x^3-1\right)-\left(8x^3-1\right)\)
\(=8x^3-8-8x^3+1\)
\(=-7\)
1) \(x^6+1\)
\(=x^6+x^4-x^4+x^2-x^2+1\)
\(=\left(x^6-x^4+x^2\right)+\left(x^4-x^2+1\right)\)
\(=x^2\left(x^4-x^2+1\right)+\left(x^4-x^2+1\right)\)
\(=\left(x^2+1\right)\left(x^4-x^2+1\right)\)
2) \(x^6-y^6\)
\(=\left(x^3+y^3\right)\left(x^3-y^3\right)\)
\(=\left(x+y\right)\left(x^2-xy+y^2\right)\left(x-y\right)\left(x^2+xy+y^2\right)\)
8a3b4-12a4b3+4a3b3
=4a3b3.(2b-3a+1)
mình có cảm giác sai sai nếu ai phát hiện nhắc dùm mình nha
b) \(3x\left(x-1\right)^2-2x\left(x+3\right)\left(x-3\right)+4x\left(x-4\right)\)
\(=3x\left(x^2-2x+1\right)-2x\left(x^2-9\right)+4x^2-16x=3x^3-6x^2+3x-2x^3+18x+4x^2-16x\)\(=x^3-2x^2+5x\)
c) \(2\left(2x+5\right)^2-3\left(4x+1\right)\left(1-4x\right)=2\left(4x^2+20x+25\right)+3\left(16x^2-1\right)\)
\(=8x^2+40x+50+48x^2-3=56x^2+40x+47\)
d) \(x\left(x+4\right)\left(x-4\right)-\left(x^2+1\right)\left(x^2-1\right)=x\left(x^2-16\right)-x^4+1=x^3-x^4-16x+1\)
e) \(\left(y-3\right)\left(y+3\right)\left(y^2+9\right)-\left(y^2+2\right)\left(y^2-2\right)=\left(y^2-9\right)\left(y^2+9\right)-y^4+4=y^4-81-y^2+4=-77\)
a, \(a^2+12a+36=a^2+2.6a+6^2=\left(a+6\right)^2\)
b, \(49m^2-25a^2=\left(7m-5a\right)\left(7m+5a\right)\)
c, \(\dfrac{4}{9}a^4-81b^2=\left(\dfrac{2}{3}a^2-9b\right)\left(\dfrac{2}{3}a^2+9b\right)\)
d, \(\left(a+1\right)^2-9x^2=\left(a+1-3x\right)\left(a+1+3x\right)\)
e, \(\left(x+4\right)^2-\left(y-3\right)^2=\left(x+4-y+3\right)\left(x+4+y-3\right)\)
f, \(27x^3-27x^2y+9xy^2-y^3\)
\(=\left(3x\right)^3-3.\left(3x\right)^2.y+3.3x.y^2-y^3\)
\(=\left(3x-y\right)^3\)
Chúc bạn học tốt!!!
Phân tích đa thcusw thành nhân tử (Phương pháp nhân hạng tử):
1. 3a - 3b + ax - bx
= 3(a - b) + x(a - b)
= (a - b)(3 + x)
2. x3 + 3x2 + 3x + 9
= x3 + 3x2 + 3x + 1 + 8
= (x + 1)3 + 8
= (x + 1 + 2)[(x + 1)2 - 2(x + 1) + 4]
= (x + 3)(x2 + 2x + 1 - 2x - 2 + 4)
= (x + 3)(x2 + 3)
3. 10ay - 5by + 2ax - bx
= 5y(2a - b) + x(2a - b)
= (2a - b)(5y + x)
4. 5a2 - 5ax - 7a + 7x
= 5a(a - x) - 7(a - x)
= (a - x)(5a - 7)
5. x2 - 3xy + x - 3x
= x(x - 3y + 1 - 3)
= x(x - 3y - 2)
6. 7x2 - 7xy - 4x + 4y
= 7x(x - y) - 4(x - y)
= (x - y)(7x - 4)
7. 3ax - 4by - 4ay + 3bx
= (3ax + 3bx) - (4ay + 4by)
= 3x(a + b) - 4y(a + b)
= (a + b)(3x - 4y)
8. 30ax - 34bx - 15a + 17b
= (30ax - 15a) - (34bx -17b )
= 15a(x - 1) - 17b(x - 1)
= (x - 1)(15a - 17b)
9. 3x2 - 3xy + 3y2 - 3xy
= 3(x2 - xy + y2 - xy)
= 3(x2 - 2xy + y2)
= 3(x - y)2
10. 12a2 - 6ab + 3b2 - 6ab
= 3(4a2 - 2ab + b2 - 2ab)
= 3(4a2 - 4ab + b2)
= 3(2a - b)2