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13 tháng 10 2021

a)-4a^3b.2a^3b^2-4a^3b(-3ab^4)
-8a^6b^3+12a^4b^3
b)2x.x^2-2x.3x+2x.4-3.x^2-3.(-3x)-3.4
2x^3-6x^2+8x-3x^2+9x-12
2x^3-9x^2+17x-12

6 tháng 9 2017

\(3y^2\left(a-3x\right)-a\left(a-3x\right)=\left(3y^2-a\right)\left(a-3x\right)\)

19 tháng 7 2018

a) 4x^2 - 12xy + 9y^2

=(2x)^2 - 2.2.3xy + (3y)^2

=(2x+3y)^2

b) 27a^3 - 64b^3

=(3a)^3 - (4b)^3

=(3a - 4b) [(3a)^2 +3a.4b +(4B)^2]

d) (2x - 6y)^2 - (3xy - 4)^2

=[ (2x - 6y)+ (3xy - 4) ] [ (2x - 6y)- (3xy - 4) ]

19 tháng 7 2018

\(1,a,4x^2-12xy+9y^2\)

\(=\left(2x\right)^2-2.3.2xy+\left(3y\right)^2\)

\(=\left(2x-3y\right)^2\)

\(b,27a^3-64b^3\)

\(=\left(3a\right)^3-\left(4b\right)^3\)

\(\left(3a-4b\right)\left(9a^2+12ab+16b^2\right)\)

b: \(x^3+\dfrac{1}{27}=\left(x+\dfrac{1}{3}\right)\left(x^2-\dfrac{1}{3}x+\dfrac{1}{9}\right)\)

c: \(x^3-3x^2+3x-1=\left(x-1\right)^3\)

e: \(a^2y^2-2axby+b^2x^2\)

\(=\left(ay\right)^2-2\cdot ay\cdot bx+\left(bx\right)^2\)

\(=\left(ay-bx\right)^2\)

f: \(100-\left(3x-y\right)^2\)

\(=\left(10-3x+y\right)\left(10+3x-y\right)\)

g: \(64x^2-\left(8a+b\right)^2\)

\(=\left(8x\right)^2-\left(8a+b\right)^2\)

\(=\left(8x-8a-b\right)\left(8x+8a+b\right)\)

3 tháng 7 2019

a)  (2a - b)(b + 4a) + 2a(b - 3a)
= 2a(b + 4a) - b(b + 4a) + 2ab - 6a^2
= 2ab + 8a^2 - b^2 - 4ab + 2ab - 6a^2
= (8a^2 - 6a^2) + (2ab + 2ab - 4ab) - b^2
= 2a^2 - b^2
b) .(3a - 2b)(2a - 3b) - 6a(a - b)
= 3a(2a - 3b) - 2b(2a - 3b) - (6a^2 - 6ab)
= 6a^2 - 9ab - (4ab - 6b^2) - (6a^2 - 6ab)
= 6a^2 - 9ab - 4ab + 6b^2 - 6a^2 + 6ab
= 6b^2 + (6a^2 - 6a^2) + (6ab - 4ab - 9ab)
= 6b^2 - 7ab

c. 5b(2x - b) - (8b - x)(2x - b)
= 10bx - 5b^2 - 8b(2x - b) + x(2x - b)
= 10bx - 5b^2 - 16bx + 8b^2 + 2x^2 - bx
= (10bx - 16bx - bx) + 2x^2 + (8b^2 - 5b^2)
= -7bx + 2x^2 + 3b^2
d. 2x(a + 15x) + (x - 6a)(5a + 2x)
= 2ax + 30x^2 + x(5a + 2x) - 6a(5a + 2x)
= 2ax + 30x^2 + 5ax + 2x^2 - 30a^2 - 12ax
= (30x^2 + 2x^2) + (2ax + 5ax - 12ax) - 30a^2
= 32x^2 - 5ax - 30a^2

Chúc bạn hok tốt !!!

4 tháng 9 2019

1) (a+2b+1)2

=a2+2a(2b+1)+(2b+1)2

=a2+4ab+2a+(2b)2+2.2b.1+12

=a2+4ab+2a+4b2+4b+1

2) (2a-b+3)2

=(2a)2 -2.2a(b-3)+(b-3)2

=4a2-4a(b-3)+b2-2b.3+32

=4a2-4ab+12a+b2 -6b+9

3) (2a-3b+1)2

=(2a)2-2.2a(3b-1)+(3b-1)2

=4a2-4a(3b-1)+(3b)2-2.3b.1+12

=4a2-4ab+4a+9b2-6b+1

a: \(=\left[\dfrac{3xy\left(x-2x^2y\right)}{3xy}+6x^2y-x\right]^2:\dfrac{1}{2}x^2\)

\(=\left[x-2x^2y+6x^2y-x\right]^2:\dfrac{1}{2}x^2\)

\(=\dfrac{16x^4y^2}{0.5x^2}=32x^2y^2\)

b: \(=\dfrac{7\left(a-b\right)^5+5\left(a-b\right)^3}{\left(a-b\right)^2}=7\left(a-b\right)^3+5\left(a-b\right)\)

c: \(=\dfrac{7\left(a-3b\right)^3+\left(a-3b\right)}{2\left(a-3b\right)}=\dfrac{7\left(a-3b\right)^2+1}{2}\)

26 tháng 7 2020

(3x^3 - 2x^2 + x + 2)(5x^2)

= 15x^5 - 10x^4 + 5x^3 + 10x^2

(3x^2 + 5x - 2)(2x^2 - 4x + 3)

= 3x^4 - 12x^3 + 9x^2 + 10x^3 - 20x^2 + 15x - 4x^2 + 8x - 6

= 6x^4 - 2x^3 - 15x^2 + 23x - 6