\(\frac{3x+1}{17}+\frac{3x+1}{19}+\frac{3x+1}{23}\)=\(\frac{3x+1}{29}+\frac{3x+1}{31}\)
Rút gọn thừa số chung :
\(.\frac{x}{3x-1}+\frac{1}{3x-1}=\frac{x}{3x+2}+\frac{3}{3x+2}\)
Đơn giản biểu thức :
\(-\frac{x}{3x+2}-\frac{3}{3x+2}+\frac{x}{3x-1}+\frac{1}{3x-1}=0\)
Giải phương trình
\(-\frac{3x-5}{\left(3x-1\right)\left(3x+2\right)}=0\)
Giải phương trình :
3x=5
\(\frac{1}{3x-1}=0\)
\(\frac{1}{3x+2}=0\)
Giải các phương trình sau:
a) \(x+\frac{2x+\frac{x-1}{5}}{3}=1-\frac{3x-\frac{1-2x}{3}}{5}\)
b) \(\frac{3x-1-\frac{x-1}{2}}{3}-\frac{2x+\frac{1-2x}{3}}{2}=\frac{\frac{3x-1}{2}}{5}\)
c) \(\frac{x-23}{24}+\frac{x-23}{25}=\frac{x-23}{26}+\frac{x-23}{27}\)
giải các pt sau:
a. x4 - 3x3 + 3x2 -x = 80
b. (x2 + x + 1) (x2 + x + 2) = 12
c. \(\frac{2+29}{31}-\frac{x+27}{33}=\frac{x+17}{43}-\frac{x-15}{45}\)
b) Đặt x2 + x + 1 = t > 0 (dễ c/m t > 0 rồi ha)
Khi đó, pt tương đương: \(t\left(t+1\right)=12\Leftrightarrow t^2+t-12=0\Leftrightarrow\left[{}\begin{matrix}t=3\\t=-4\left(L\right)\end{matrix}\right.\)
t = 3 suy ra \(x^2+x+1=3\Leftrightarrow x^2+x-2=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-2\end{matrix}\right.\)
Vậy...
c) Chị xem lại đề giúp em ạ.
3) \(\frac{1-x}{x+1}-\frac{3+2x}{x+1}=0\)
13) \(\frac{x+2}{x}-\frac{x^2+5x+4}{x\left(x+2\right)}=\frac{x}{x+2}\)
14) \(\frac{1}{x+1}-\frac{5}{x-2}=\frac{20}{\left(x+1\right)\left(2-x\right)}\)
16) \(\frac{x+5}{x-5}-\frac{x-5}{x+5}=\frac{20}{x^2-25}\)
17) \(\frac{3x+2}{3x-2}-\frac{6}{2+3x}=\frac{9x^2}{9x^2-4}\)
18) \(\frac{x-1}{x}+\frac{1}{x+1}=\frac{2x-1}{2x^2+2}\)
19) \(\frac{2}{x+1}-\frac{3x+1}{\left(x+1\right)}=\frac{1}{\left(x+1\right)\left(x-2\right)}\)
20) \(\frac{x+5}{3x-6}-\frac{1}{2}=\frac{2x-3}{2x-4}\)
\(A=\left(\frac{x+1}{3x-1}-\frac{1}{3x+1}+\frac{3x}{9x^2-1}\right):\left(1-\frac{3x-2}{3x+1}\right)\)
Rút gọn A
Giải phương trình sau;
a) \(125x^3-\left(2x+1\right)^3-\left(3x-1\right)^3=0\)
b) \(\left(x-1\right)^3+\left(x+1\right)^3=8\left(x-1\right)^3\)
c) \(\frac{x+19}{27}+\frac{x+17}{29}=\frac{x+15}{31}-\frac{x+13}{33}\)
Giải các phương trình sau:
a) \(125x^3-\left(2x+1\right)^3-\left(3x-1\right)^3=0\)
b) \(\left(x-1\right)^3+\left(x+1\right)^3=8\left(x-1\right)^3\)
c)\(\frac{x+19}{27}+\frac{x+17}{29}=\frac{x+15}{31}-\frac{x+13}{33}\)
1.Tìm x :
a)1 - 7x = 3x - 4
2.Tính
a)-2013 . 2028 + 4028 . 26
b)\(\left(\frac{1515}{1616}+\frac{10}{170}\right)-\left(\frac{150}{160}-\frac{16}{17}\right)\)
c)\(\frac{1}{3^1}+\frac{1}{3^2}+\frac{1}{3^3}+...\frac{1}{3^{99}}\)
d)\(\frac{5}{17}+\frac{-4}{7}-\frac{20}{31}+\frac{12}{17}-\frac{11}{31}\)
e)\(\frac{155-\frac{10}{7}-\frac{5}{11}+\frac{5}{23}}{403-\frac{20}{7}-\frac{13}{13}_{ }+\frac{13}{23}}\)
a, 1 - 7x = 3x - 4
=> -7x - 3x = - 4 - 1
=> - 10x = - 5
=> x = 1/2
vậy_
b, đặt \(A=\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^{99}}\)
\(3A=1+\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^{98}}\)
\(3A-A=1-\frac{1}{3^{99}}\)
\(A=\frac{1-\frac{1}{3^{99}}}{2}\)
mk chỉ bt lm mấy phần hui à!
d)\(\frac{5}{17}+\frac{-4}{7}-\frac{20}{31}+\frac{12}{17}-\frac{11}{31}\)\(=\left(\frac{5}{17}+\frac{12}{17}\right)+\left(\frac{-20}{31}-\frac{11}{31}\right)+\frac{-4}{7}\)
\(=\frac{17}{17}+\frac{-31}{31}+\frac{-4}{7}\)\(=1+\left(-1\right)+\frac{-4}{7}\)\(=0+\frac{-4}{7}\)\(=-\frac{4}{7}\)
e)\(\frac{155-\frac{10}{7}-\frac{5}{11}+\frac{5}{23}}{403-\frac{20}{7}-\frac{13}{3}+\frac{13}{23}}\)
mk xl,mk ko bt lm các phần còn lại!
\(\frac{12}{1-9x^2}=\frac{1-3x}{1+3x}-\frac{1+3x}{1-3x}\) giải dùm minh nhá
Câu hỏi của Nguyễn Nhã Linh - Toán lớp 8 - Học toán với OnlineMath
Bạn tham khảo câu b nhé!
\(\frac{12}{\left(1-3x\right)\left(1+3x\right)}\)= \(\frac{1-3x}{1+3x}\)- \(\frac{1+3x}{1-3x}\) (đkxđ: x khác +-(1/3)) \(\frac{12}{\left(1-3x\right)\left(1+3x\right)}\)=\(\frac{\left(1-3x\right)\left(1-3x\right)-\left(1+3x\right)\left(1+3x\right)}{\left(1+3x\right)\left(1-3x\right)}\) \(12=\left(1-6x+9x^2\right)-\left(1+6x+9x^2\right)\) \(12=1-6x+9x^2-1-6x-9x^2\) \(12=-12x \\ \) \(-1=x\)