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a) \(\left(6x^3y^2-4x^2y^3-10x^2y^2\right):2xy\)
=\(\left(6x^3y^2:2xy\right)-\left(4x^2y^3:2xy\right)-\left(10x^2y^2:2xy\right)\)
\(=3x^2y-2xy^2-5xy\)
b) \(\dfrac{2y}{x-2}+\dfrac{5y}{x-2}\)
=\(\dfrac{2y+5y}{x-2}\)
=\(\dfrac{7y}{x-2}\)
c)\(\dfrac{xy}{3x-y}+\dfrac{3x^2}{y-3x}\)
\(=\dfrac{xy}{3x-y}-\dfrac{3x^2}{3x-y}\)
=\(\dfrac{x\left(y-3x\right)}{3x-y}\)
=\(\dfrac{-x\left(3x-y\right)}{3x-y}\)
=-x
d)\(\dfrac{x-1}{6x+12}.\dfrac{x+2}{x-1}\)
=\(\dfrac{\left(x-1\right)\left(x+2\right)}{6\left(x+2\right)\left(x-1\right)}\)
=\(\dfrac{1}{6}\)
a ) \(\left(5x+2y\right)^2=25x^2+20xy+4y^2\)
b ) \(\left(-3x+2\right)^2=9x^2-12x+4\)
c ) \(\left(\dfrac{2}{3}x+\dfrac{1}{3}y\right)^2=\dfrac{4}{9}x^2+\dfrac{4}{9}xy+\dfrac{1}{9}y^2\)
d ) \(\left(2x-\dfrac{5}{2}y\right)^2=4x^2-10xy+\dfrac{25}{4}y^2\)
e ) \(\left(x+\dfrac{4}{3}y^2\right)^2=x^2+\dfrac{8}{3}xy^2+\dfrac{16}{9}y^4\)
f ) \(\left(2x^2+\dfrac{5}{3}y\right)^2=4x^4+\dfrac{20}{3}x^2y+\dfrac{25}{9}y^2\)
a) (5x-y)2 = (5x)2 - 2.5x.y + y2 = 25x2 - 10xy +y2
b) (2x + y2 )3 = (2x)3 - 3.(2x)2.y2 + 3.2x.(y2)2 - (y2)3 = 8x3 - 12x2y2 + 6xy4 - y6
c) (x + \(\dfrac{1}{4}\))2 = x2 + 2.x.\(\dfrac{1}{4}\) + (\(\dfrac{1}{4}\))2 = x2 + \(\dfrac{1}{2}\).x + \(\dfrac{1}{16}\)
d) (\(\dfrac{2}{3}\)x2 - \(\dfrac{1}{2}\)y)3 = (\(\dfrac{2}{3}\)x2)3 - 3.(\(\dfrac{2}{3}\)x2)2. \(\dfrac{1}{2}\)y + 3.\(\dfrac{2}{3}\)x2. ( \(\dfrac{1}{2}\)y)2 - (\(\dfrac{1}{2}\)y)3
= \(\dfrac{8}{27}\)x6 - \(\dfrac{2}{3}\)x4y + \(\dfrac{1}{2}\)x2y2 - \(\dfrac{1}{8}\)y3
câu b) của bạn làm sai rồi. hằng đẳng thức số 4 là : (A+B)3= A3+3A2B+3AB2+B3
sửa lại:
(2x+y2)3=2x3+3.(2x)2.y2+3.2x.(y2)2+(y2)3=8x3+12x2y2+6xy4+y6
$a)$ \(x^{12}:\left(-x\right)^6\)
\(=x^{12}:x^6\)
\(=x^{12-6}\)
\(=x^6\)
$b) $ \(\left(-x\right)^7:\left(-x\right)^5\)
\(=\left(-x\right)^{7-5}\)
\(=\left(-x\right)^2\)
\(=x^2\)
$c)$ \(5x^2y^4:10x^2y\)
\(=\dfrac{1}{2}y^3\)
$e)$ \(\left(-xy\right)^{14}:\left(-xy\right)^7\)
\(=\left(-xy\right)^{14-7}\)
\(=\left(-xy\right)^7\)
Các câu còn lại tương tự nha bạn!
a; \(=x^5-2x^4-x^3-x^3-x^2=x^5-2x^4-2x^3-x^2\)
b: \(=2x^3-6x^2+x^2-3x+x-3\)
\(=2x^3-5x^2-2x-3\)
c: \(=6x^3y^2-3x^3+3x^2-2x^2y^3+x^2y-xy\)
d: \(=x^3-x^3y+x^3y-x^2y^2+xy^3-y^4\)
\(=x^3-x^2y^2+xy^3-y^4\)
Bài 2:
\(=\dfrac{x^2\left(x^2+4\right)-2x\left(x^2+4\right)}{x^2+4}=x^2-2x\)
Bài 1:
a: \(=\left(\dfrac{2}{3}:\dfrac{-1}{9}\right)\cdot x^4y^2z^6=-6x^4y^2z^6\)
b: \(=-12x^8-21x^5\)
c: =x^3+8
d: \(=125x^3-75x^2+15x-1\)
câu a hình như sai đề rồi bạn ạ