bài 10
a, \(\dfrac{5xy-4y}{2x^2y^3}\) + \(\dfrac{3xy+4y}{2x^2y^3}\)
Thực hiện các phép tính sau :
a) \(\dfrac{3x-5}{7}+\dfrac{4x+5}{7}\)
b) \(\dfrac{5xy-4y}{2x^2y^3}+\dfrac{3xy+4y}{2x^2y^3}\)
c) \(\dfrac{x+1}{x-5}+\dfrac{x-18}{x-5}+\dfrac{x+2}{x-5}\)
A = \(\dfrac{5xy^2-3z}{3xy}+\dfrac{4x^2y+3z}{3xy}\)
B = \(\dfrac{3y+5}{y-1}+\dfrac{-y^2-4y}{1-y}+\dfrac{y^2+y+7}{y-1}\)
C = \(\dfrac{6x}{x^2-9}+\dfrac{5x}{x-3}+\dfrac{x}{x+3}\)
D = \(\dfrac{1-3x}{2x}+\dfrac{3x-2}{2x-1}+\dfrac{3x-2}{2x-4x^2}\)
E = \(\dfrac{x^3+2x}{x^3+1}+\dfrac{2x}{x^2-x+1}+\dfrac{1}{x+1}\)
b: \(B=\dfrac{3y+5}{y-1}-\dfrac{-y^2-4y}{y-1}+\dfrac{y^2+y+7}{y-1}\)
\(=\dfrac{3y+5+y^2+4y+y^2+y+7}{y-1}\)
\(=\dfrac{2y^2+8y+12}{y-1}\)
rút gọn
5xy-4y/3x^2y^3+3xy+4/2x^2y^3
Thực hiện phép tính
\(\frac{5xy-4y}{2x^2y^3}+\frac{3xy-4y}{2x^2y^3}\)
\(\frac{4x-1}{3x^2y}-\frac{7x-1}{3x^2y}\)
Lời giải:
\(\frac{5xy-4y}{2x^2y^3}+\frac{3xy-4y}{2x^2y^3}=\frac{8xy-8y}{2x^2y^3}=\frac{8y(x-1)}{2x^2y^3}=\frac{4(x-1)}{x^2y^2}\)
\(\frac{4x-1}{3x^2y}-\frac{7x-1}{3x^2y}=\frac{-3x}{3x^2y}=\frac{-1}{xy}\)
\(\left\{{}\begin{matrix}4x^2+3xy-2y^2=2x+4y\\\dfrac{x^2\left(2x-y\right)}{x+2y}=\dfrac{1}{2}\end{matrix}\right.\)
Tìm x;y;z biết :
1) \(\dfrac{1+2y}{6}=\dfrac{3+4y}{5}=\dfrac{9+6y}{2x+1}\)
2) \(\dfrac{1+2y}{18}=\dfrac{1+4y}{28}=\dfrac{1+6y}{6x}\)
2) Áp dụng tính chất dãy tỉ số bằng nhau ta có:
\(\dfrac{1+2y}{18}=\dfrac{1+6y}{6x}=\dfrac{1+2y+1+6y}{18+6x}=\dfrac{2\left(1+4y\right)}{2\left(9+3x\right)}=\dfrac{1+4y}{9+3x}\)
⇒ \(\dfrac{1+4y}{9+3x}=\dfrac{1+4y}{28}\)
⇒\(9+3x=28\)
⇒\(3x=19\)
⇒\(x=\dfrac{19}{3}\)
bạn thay vào là tìm được y
1. x^2-y^2-2x+2y 2. x^3-x+3x^2y+3xy^2+y^3-y. 3. 4x^4y^4+1. 4. x^2-2x-4y^2-4y. 5.x^3-x^2-x+1. 6.x^2y-x^3-9y+9x. 7.x^3-2x^2+x-xy^2. 8.x^2-2x-4y^2-4y.
Ói , hoa mắt chóng mặt nhức đầu ,
cho 2 đa thức A= \(-4x^5y^3+x^4y^3-3x^2y^3z^2-x^4y^3+x^2y^3z^2-2y^4\)
a) thu gọn rồi tìm bậc đa thức A
b) tìm đa thức B biết rằng B\(-2x^2y^3z^2+\dfrac{2}{3}y^4-\dfrac{1}{5}x^4y^3=A\)
a: \(A=-4x^5y^3-2x^2y^3z^2-2y^4\)
b: \(B=-4x^5y^3-2x^2y^3z^2-2y^4+2x^2y^3z^2-\dfrac{2}{3}y^4+\dfrac{1}{5}x^4y^3=-4x^5y^3+\dfrac{1}{5}x^4y^3-\dfrac{8}{3}y^4\)
Quy đồng mẫu thức các phân thức sau :
a) \(\dfrac{25}{14x^2y};\dfrac{14}{21xy^5}\)
b) \(\dfrac{11}{102x^4y};\dfrac{3}{34xy^3}\)
c) \(\dfrac{3x+1}{12xy^4};\dfrac{y-2}{9x^2y^3}\)
d) \(\dfrac{1}{6x^3y^2};\dfrac{x+1}{9x^2y^4};\dfrac{x-1}{4xy^3}\)
e) \(\dfrac{3+2x}{10x^4y};\dfrac{5}{8x^2y^2};\dfrac{2}{3xy^5}\)
f) \(\dfrac{4x-4}{2x\left(x+3\right)};\dfrac{x-3}{3x\left(x+1\right)}\)
g) \(\dfrac{2x}{\left(x+2\right)^3};\dfrac{x-2}{2x\left(x+2\right)^2}\)
h) \(\dfrac{5}{3x^3-12x};\dfrac{3}{\left(2x+4\right)\left(x+3\right)}\)
thực hiện phép tính:
a,\(\left(9x^2y^3-15x^4y^4\right):3x^2y-\left(2-3x^2y\right)y^2\)
b,\(\left(6x^2-xy\right):x+\left(2x^3y+3xy^2\right):xy-\left(2x-1\right)x\)
c,\(\left(x^2-xy\right):x-+\left(6x^2y^5-9x^3y^4+15x^4y^2\right):\dfrac{3}{2}x^2y^3\)