a ) \(\left(x+y\right)^5=x^5+5x^4y+10x^3y^2+5xy^4+y^5\)

b ) \(\left(x-3y\right)^6=\left[x+\left(-3y\right)\right]^6\)

                       \(=x^6+6x^5\left(-3y\right)+15x^4\left(-3y\right)^2+20x^3\left(-3y\right)^3+15x^2\left(-3y\right)^4+6x\left(-3y\right)^5+\left(-3y\right)^6\)

\(=x^6-18x^5y+135x^4y^2-540x^3y^3+1215x^2y^4-1458xy^5+729y^6\)

Chúc bạn học tốt 

a)

b)

\(a^4+b^4=\left(a^4+2a^2b+b^4\right)-2a^2b^2\)

\(=\left(a^2+b^2\right)^2-\left(\sqrt{2}.a.b\right)^2=\left(a^2+b^2+\sqrt{2}.a.b\right)\left(a^2+b^2+\sqrt{2}.a.b\right)\)

@milimet ơi,bạn đó làm đúng oy,thế này là ngắn nhất mà

chỉ có thể là \(\left(a+b\right)^2-2ab\)thôi bạn ơi

T I C K nha 

CHÚC BẠN HỌC TỐT

\(\left(2a^2+1\right)^3=\left(2a^2+1\right)\left(2a^2+1\right)\left(2a^2+1\right)\\ =\left(4a^4+4a^2+1\right)\left(2a^2+1\right)\\ =8a^6+8a^4+2a^2+4a^4+4a^2+1\\ =8a^6+12a^4+6a^2+1\)

\(\left(2a^2+1\right)^3=8a^6+12.a^4+6a^2+1\)

(a+b+c)²=(a+b)²+2(a+b)c+c²

          =a²+2ab+b²+2ac+2bc+c²

(a+b-c)²=(a+b)²-2(a+b)c+c²

           =a²+2ab+b²-2ab-2bc+c²

(a-b-c)²=(a-b)²-2(a-b)c+c²

        =a²-2ab+b²-2ac+2bc+c²

a\(=\frac{1}{4}x^2+2.\frac{1}{2}x.1+1=\frac{1}{4}x^2+x+1\)

b\(=4x^2-2.2x.\frac{1}{3}+\frac{1}{9}=4x^2-\frac{4}{3}x+\frac{1}{9}\)

Bạn học tốt nha >>>>>>

nha

a/\(\left(\frac{1}{2}x+1\right)^2=\frac{1}{4}x^2+x+1^2\)

b/\(\left(2x-\frac{1}{3}\right)^3=8x^3-2x+\frac{2}{3}x-\frac{1}{27}\)

k nha

Giải:

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

\(=\left(3x^2\right)^2-2.3x.2y+\left(2y^3\right)^2\)

\(=9x^4-12xy+4y^6\)

Vậy ...

b) \(\left(-2x^2-3\right)^2\)

\(=\left(-2x^2\right)^2-2.2x^2.3+3^2\)

\(=4x^4-12x^2+9\)

Vậy ...

a, \(25x^2+30xy+9y^2\)

b, \(x^2-4xy+4y^2\)

c${\left(2x-3\right)}^{}$${}^{}$= \(4x^2-12x+9\)

a) \(\left(2x^2-1\right)^2\)

\(=4x^4-4x^2+1\)

b)\(\left(\dfrac{1}{2}x+3y^2\right)^2\)

\(=\dfrac{1}{4}x^2+3xy^2+9y^4\)

a, \(\left(3-x\right)^2=9-6x+x^2\)

b, \(\left(x-\frac{1}{2}\right)^2=x^2-x+\frac{1}{4}\)

c, \(\left(2x+y\right)^2=4x^2+4xy+y^2\)