\(M=\dfrac{1}{337}.2\dfrac{1}{291}-\dfrac{290}{291}.\dfrac{1}{337}-\dfrac{2}{291.337}\)
\(M=\dfrac{1}{337}\left(2+\dfrac{1}{291}\right)-\left(1-\dfrac{1}{291}\right).\dfrac{1}{337}-2.\dfrac{1}{291.337}\)
Thay a = 1/337 ; b = 1/291 vào M, ta được
\(M=a\left(2+b\right)-\left(1-b\right)a-2ab\)
\(M=2a+ab-a+ab-2ab\)
\(M=a\)
\(M=\dfrac{1}{337}\)
cho \(\dfrac{1}{a}+\dfrac{1}{b}+\dfrac{1}{c}=2\) và\(\dfrac{1}{a^2}+\dfrac{1}{b^2}+\dfrac{1}{c^2}=2\)
CMR: a+b+c=abc
sắp thi HK1 rùi giúp vs
Cho M= \(\left(x-a\right)\left(x-b\right)+\left(x-b\right)\left(x-c\right)+x^2\)
M the a,b,c biết \(x=\dfrac{1}{2}a+\dfrac{1}{2}b+\dfrac{1}{2}c\)
Ai giups mk vs ai nhanh mk sẽ vote nha
Tính giá trị của biểu thức sau:
\(A=\dfrac{1}{3579}.7\dfrac{1}{197}-3\dfrac{3588}{3579}.\dfrac{2}{197}-\dfrac{7}{3589}-\dfrac{3}{3579.197}\)
\(B=\dfrac{3}{229}\left(2+\dfrac{1}{433}\right)-\dfrac{1}{229}.\dfrac{432}{433}-\dfrac{4}{229.433}\)
Thực hiện các phép tính sau:
a).\(\left(\dfrac{2x+1}{2x-1}-\dfrac{2x-1}{2x+1}\right):\dfrac{4x}{10x-5}\)
b). \(\left(\dfrac{1}{x^2+1}-\dfrac{2-x}{x+1}\right):\left(\dfrac{1}{x}+x-2\right)\)
c). \(\dfrac{1}{x-1}-\dfrac{x^3-x}{x^2+1}.\left(\dfrac{1}{x^2-2x+1}+\dfrac{1}{1-x^2}\right)\)
d). \(\left(\dfrac{x^2+xy}{x^3+x^2y+xy^2+y^3}+\dfrac{y}{x^2+y^2}\right):\left(\dfrac{1}{x-y}-\dfrac{2xy}{x^3-x^2y+xy^2-y^3}\right)\)
bài 2 : cho x,y,z >0 thỏa mãn
\(\dfrac{1}{x}+\dfrac{1}{y}+\dfrac{1}{z}>\dfrac{1}{\sqrt{xy}+}\dfrac{1}{\sqrt{yz}}+\dfrac{1}{\sqrt{xz}}\)
Giải phương trình:
a)\(\dfrac{1}{x+1}-\dfrac{5}{x-2}=\dfrac{15}{\left(x+1\right)\left(2-x\right)}\)
b) \(1+\dfrac{x}{3-x}=\dfrac{5x}{\left(x+2\right)\left(3-x\right)}+\dfrac{2}{x+2}\)
c)\(\dfrac{6}{x-1}-\dfrac{4}{x-3}=\dfrac{8}{\left(x-1\right)\left(3-x\right)}\)
d) \(\dfrac{x+2}{x-2}-\dfrac{1}{x}=\dfrac{2}{x\left(x-2\right)}\)
Tìm x
\(\dfrac{4}{5}x^2\left(\dfrac{x}{3}-\dfrac{1}{2}\right)-\left(\dfrac{1}{5}x-\dfrac{2}{3}\right)\left(\dfrac{4x^2}{3}+1\right)=\dfrac{22}{45}x^2\)
Cho biểu thức:
A=\(\left(\dfrac{x}{x^2-4}+\dfrac{2}{2-x}+\dfrac{1}{x+2}\right):\left(x-2+\dfrac{10-x^2}{x+2}\right)\)
a. Rút gọn A
b. Tính giá trị biểu thức A tại x, biết /x/=\(\dfrac{1}{2}\)
c. Tìm giá trị của x để A<0
\(B=4\dfrac{1}{113}x\dfrac{1}{371}-\dfrac{2}{113}x5\dfrac{370}{371}-\dfrac{3}{113x117}-\dfrac{4}{371}\)
Giúp mình với@@!