Bài 1 Tính
a, \((3x-2y)^2\)
b, \((2x-\frac{1}{2})^2\)
c, \((\frac{x}{2}-y)(\frac{x}{2}+y)\)
d,\((x+\frac{1}{3})^3\)
e,\((x-2)(x^2+2x+4)\)
Bài 2 Chứng minh các đẳng thức
a. \((x+y)^2-y^2=x(x+2y)\)
b,\((x^2+y^2)^2-(2xy)^2=(x+y)^2(x-y)^2\)
c,\((x+y)^3=x(x-3y)^2+y(y-3x)^2\)
Bài 3 Chứng minh rằng
a, \((a+b)^3+(a-b)^3=2a(a^2+3b^2)\)
b, \((a+b)^3-(a-b)^3=2b(b^2+3a^2)\)
Các bạn giúp mình nha
1.a (3x-2y)2= (3x)2 - 2. 3x . 2y - (2y)2 = 9x2 - 12xy - 4y2
2.b (2x - 1/2)2 = (2x)2 - 2.2x.1/2 - (1/2)2= 4x2 - 2 - 1/4
3.c (x/2 - y) (x/2+y)= (x/2)2 - (y)2 = x/4 - y2
Bài 1 :
\(\left(3x-2y\right)^2=9x^2-12xy+4y^2\)
\(\left(2x-\frac{1}{2}\right)^2=4x^2-4x+\frac{1}{4}\)
\(\left(\frac{x}{2}-y\right)\left(\frac{x}{2}+y\right)=\frac{x^2}{4}-y^2\)
\(\left(x+\frac{1}{3}\right)^3=x^3+x^2+\frac{1}{3}x+\frac{1}{27}\)
\(\left(x-2\right)\left(x^2+2x+2^2\right)=x^3-8\)