thực hiện phép tính :(y+3)^3-(3-y)^2-54y
Những câu hỏi liên quan
thực hiện phép tính
a) (x+3y)(2x^2y -6xy^2)
b) (6x^5y^2 -9x^4y^3 +15x^3y^4) : 3x^3y^2
c) (2x+3)^2 + (2x+5)^2 -2(2x+3)(2x+5)
d) (y+3)^3 -(3-y)^2 -54y
a) (x + 3y) (2x2y - 6xy2)
= (x + 3y) + 2xy (x - 3y)
= 2xy [(x + 3y) (x - 3y)]
= 2xy (x2 - 3y2)
b) (6x5y2 - 9x4y3 + 15x3y4) : 3x3y2
= (6x5y2 : 3x3y2) + (-9x4y3 : 3x3y2) + (15x3y4 : 3x3y2)
= [(6 : 3) (x5 : x3) (y2 : y2)] + [(-9 : 3) (x4 : x3) (y3 : y2)] + [(15 : 3) (x3 : x3) (y4 : y2)]
= 2x2 + (-3xy) + 5y2
= 2x2 - 3xy + 5y2
#Học tốt!!!
1, thực hiện các phép tính
a,\(\left(x+3y\right)\left(2x^2y-6xy^2\right)\)
b, \(\left(6x^5y^2-9x^4y^3+15x^3y^4\right):3x^3y^2\)
c, \(\left(2x+3\right)^2+\left(2x+5\right)^2-2\left(2x+3\right)\left(2x+5\right)\)
d, \(\left(y+3\right)^3-\left(3-y\right)^2-54y\)
a) \(\left(x+3y\right)\left(2x^2y-6xy^2\right)\)
\(=x\left(2x^2y-6xy^2\right)+3y\left(2x^2y-6xy^2\right)\)
\(=2x^3y-6x^2y^2+6x^2y^2-18xy^3\)
\(=2x^3y-18xy^3\)
b) \(\left(6x^5y^2-9x^4y^3+15x^3y^4\right):3x^3y^2\)
\(=6x^5y^2:3x^3y^2-9x^4y^3:3x^3y^2+15x^3y^4:3x^3y^2\)
\(=2x^2-3xy+5y^2\)
c) \(\left(2x+3\right)^2+\left(2x+5\right)^2-2\left(2x+3\right)\left(2x+5\right)\)
\(=\left(2x+3-2x-5\right)^2\)
\(=\left(-2\right)^2=4\)
d) \(\left(y+3\right)^3-\left(3-y\right)^2-54y\)
\(=y^3+9y^2+27y+27-\left(x^2-6x+9\right)-54y\)
\(=y^3+9y^2-27y+27-x^2+6y-9\)
\(=y^3+9y^2-x^2-21y+18\)
thực hiện phép tính
a) (x+3y)(2x^2y -6xy^2)
b) (6x^5y^2 -9x^4y^3 +15x^3y^4) : 3x^3y^2
c) (2x+3)^2 + (2x+5)^2 -2(2x+3)(2x+5)
d) (y+3)^3 -(3-y)^2 -54y
a)
b) \(\left(6x^5y^2-9x^4y^3+15x^3y^4\right):3x^3y^2\)
\(=2x^2-3xy+5y^2.\)
c)
Chúc bạn học tốt!
Thực hiện phép tính sau:
\(\dfrac{3}{2x^2+y}+\dfrac{5}{xy^2}+\dfrac{x}{y^3}\)
\(\dfrac{3}{2x^2+y}+\dfrac{5}{xy^2+}+\dfrac{x}{y^3}\)
=\(\dfrac{3xy^5}{xy^2.y^3\left(2x^2+y\right)+}+\dfrac{10y^3x^2+5y^4}{xy^2.y^3\left(2x^2+y\right)}+\dfrac{2x^4y^2+x^2y^3}{xy^2.y^3\left(2x^2+y\right)}\)
=\(\dfrac{3xy^5+10y^3x^2+5y^4+2x^4y^2+x^2y^3}{xy^5\left(2x^2+y\right)}\)
=\(\dfrac{3xy^5+11y^3x^2+5y^4+2x^4y^2}{xy^5\left(2x^2+y\right)}\)
ủa đáp án cứ sao sao:<
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1, Thực hiện phép tính
(\(\dfrac{2}{3}\)x\(^3\)y\(^2\)-x\(^2\)y+6x\(^3\)) : (\(\dfrac{-1}{4}\)x\(^2\))
thực hiện phép tính sau\(\dfrac{1}{x-y}-\dfrac{3xy}{x^3-y^3}+\dfrac{x-y}{x^2+xy+y^2}\)
MTC = (x - y)(x2 + xy + y2)
\(\dfrac{1}{x-y}-\dfrac{3xy}{x^3-y^3}+\dfrac{x-y}{x^2+xy+y^2}\)
\(=\dfrac{x^2+xy+y^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}-\dfrac{3xy}{\left(x-y\right)\left(x^2+xy+y^2\right)}+\dfrac{\left(x-y\right)^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{x^2+xy+y^2-3xy+\left(x-y\right)^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{x^2+xy+y^2-3xy+x^2-2xy+y^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2x^2-4xy+2y^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2\left(x^2-2xy+y^2\right)}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2\left(x-y\right)^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2\left(x-y\right)}{x^2+xy+y^2}\)
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1/x-y-3xy/x^3-y^3+x-y/x^2+xy+y^2
=1/x-y+-3xy/(x-y)(x^2+xy+y^2)+x-y/x^2+xy+y^2
=x^2+xy+y^2/(x-y)(x^2+xy+y^2)+-3xy/(x-y)(x^2+xy+y^2)+x^2-2xy+y^2/(x-y)(x^2+xy+y^2)
=x^2+xy+y^2-3xy+x^2-2xy-y^2/(x-y)(x^2+xy+y^2)
=2x^2-5xy/(x-y)(x^2+xy+y^2)
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MTC = (x - y)(x2 + xy + y2)
\(\dfrac{1}{x-y}-\dfrac{3xy}{x^3-y^3}+\dfrac{x-y}{x^2+xy+y^2}\)
\(=\dfrac{x^2+xy+y^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}-\dfrac{3xy}{\left(x-y\right)\left(x^2+xy+y^2\right)}+\dfrac{\left(x-y\right)^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{x^2+xy+y^2-3xy+\left(x-y\right)^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{x^2+xy+y^2-3xy+x^2-2xy+y^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2x^2-4xy+2y^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2\left(x^2-2xy+y^2\right)}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2\left(x-y\right)^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2\left(x-y\right)}{x^2+xy+y^2}\)
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Thực hiện phép tính :bài 1 :thực hiện phép tính :
Bài 3: phân tích thành nhân tử:3/6x(x-y)-9y^2+9xyBài 4:Tìm x, biết:
1/ (x-1)(x^2+x+1)-x^3-6x=11
2/ 16x^2-(3x-4)^2=0
3/ x^3-x^2+3-3x=0
4/ x-1/x+2=x+2/x+1
5/1/x+2/x+1=0
6/ 9-x^2/x : (x-3)=1
Xem chi tiết
Bài 3: phân tích thành nhân tử:3/6x(x-y)-9y^2+9xyBài 4:Tìm x, biết:
1/ (x-1)(x^2+x+1)-x^3-6x=11
2/ 16x^2-(3x-4)^2=0
3/ x^3-x^2+3-3x=0
4/ x-1/x+2=x+2/x+1
5/1/x+2/x+1=0
6/ 9-x^2/x : (x-3)=1
Bài 3:
3: \(6x\left(x-y\right)-9y^2+9xy\)
\(=6x\left(x-y\right)+9xy-9y^2\)
\(=6x\left(x-y\right)+9y\left(x-y\right)\)
\(=\left(x-y\right)\left(6x+9y\right)\)
\(=3\left(2x+3y\right)\left(x-y\right)\)
Bài 4:
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SGK Toán 8 tập 1 – Chân trời sáng tạo
23 tháng 7 2023 lúc 15:38
Thực hiện các phép tính sau:
a) \(18{x^4}{y^3}:12{\left( { - x} \right)^3}y\)
b) \({x^2}{y^2} - 2x{y^3}:\left( {\dfrac{1}{2}x{y^2}} \right)\)
a) \(18x^4y^3:12\left(-x\right)^3y\)
\(=\left(18:-12\right)\left(x^4:x^3\right)\left(y^3:y\right)\)
\(=-\dfrac{3}{2}xy^2\)
b) \(x^2y^2-2xy^3:\dfrac{1}{2}xy^2\)
\(=\dfrac{xy^2\left(x-2y\right)}{\dfrac{1}{2}xy^2}\)
\(=\dfrac{x-2y}{\dfrac{1}{2}}\)
\(=2x-4y\)
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Thực hiện phép tính cộng
\(\dfrac{1}{x-y}\)+\(\dfrac{3xy}{y^3-x^3}\)+\(\dfrac{x-y}{x^2+xy+y^2}\)
GIÚP MÌNH VS Ạ
Ta có:
\(\dfrac{1}{x-y}+\dfrac{3xy}{y^3-x^3}+\dfrac{x-y}{x^2+xy+y^2}\\ =\dfrac{x^2+xy+y^2-3xy+\left(x-y\right)^2}{x^3-y^3}\\ =\dfrac{2\left(x-y\right)^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\\ =\dfrac{2\left(x-y\right)}{x^2+xy+y^2}\)
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\(\dfrac{1}{x-y}+\dfrac{3xy}{y^3-x^3}+\dfrac{x-y}{x^2+xy+y^2}\) \(=\dfrac{x^2+xy+y^2}{x^3-y^3}-\dfrac{3xy}{x^3-y^3}+\dfrac{\left(x-y\right)^2}{x^3-y^3}\)
\(=\dfrac{x^2+xy+y^2-3xy+x^2-2xy+y^2}{x^3-y^3}\)
\(=\dfrac{2x^2+2y^2-4xy}{x^3-y^3}\)
\(=\dfrac{2x^2-2xy-2xy+2y^2}{x^3-y^3}\)
\(=\dfrac{2x\left(x-y\right)-2y\left(x-y\right)}{x^3-y^3}\)
\(=\dfrac{\left(2x-2y\right)\left(x-y\right)}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2x-2y}{x^2+xy+y^2}\)
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