Tìm C:
C=\(\frac{5}{111111}\)+\(\frac{5}{222222}\)-\(\frac{5}{3\text{x}7\text{x}11\text{x}13\text{x}37}\)
ai làm đúng và nhanh nhất cho 2 l-i-k-e
C=\(\frac{5}{111111}\)+\(\frac{1}{222222}\)-\(\frac{4}{3\text{x}7\text{x}11\text{x}13\text{x}37}\)
tính C
C=5/1111111+5/222222-5/111111
C=(5/111111+5/111111-5/222222)
C=5/222222
tính nhanh
\(\frac{3\text{x}5\text{x}7\text{x}11\text{x}13\text{x}37-10101}{1212120+40404}\)
ai làm đúng đầu tiên cho 2 like
\(=\frac{3\text{x}5x7x11\text{x}13\text{x}37-3\text{x}7\text{x}13\text{x}37}{2^3x3^2x5\text{x}7\text{x}13\text{x}37+2^2x3\text{x}7\text{x}13\text{x}37}=\frac{3\text{x}7\text{x}13\text{x}37\left(5\text{x}11-1\right)}{2^2x3\text{x}7\text{x}13\text{x}37\left(2\text{x}3\text{x}5+1\right)}\)
\(=\frac{54}{2^2x31}=\frac{54}{124}=\frac{27}{62}\) thử lại kết quả rồi nhé
1) Tính nhanh
a) A=\(\frac{3}{11\text{x}13}+\frac{3}{13\text{x}15}+\frac{3}{15\text{x}17}+...+\frac{3}{97\text{x}99}\)
b) B=\(\frac{4}{7\text{x}31}+\frac{6}{7\text{x}11}+\frac{9}{10\text{x}41}+\frac{7}{10\text{x}57}\)
3) Chứng tỏ phân số \(\frac{8n+5}{6n+4}\)tối giản với mọi số nguyên khác 0
\(A=\frac{3}{2}\times\left(\frac{1}{13\times11}+\frac{1}{13\times15}+\frac{1}{15\times17}+.....+\frac{1}{97\times99}\right)\)
\(A=\frac{3}{2}\times\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+\frac{1}{15}-\frac{1}{17}+......+\frac{1}{97}-\frac{1}{99}\right)\)
\(A=\frac{3}{2}\times\left(\frac{1}{11}-\frac{1}{99}\right)\)
\(A=\frac{3}{2}\times\frac{8}{99}\)
\(A=\frac{4}{33}\)
b] \(\frac{A}{5}=\frac{4}{31.35}+\frac{6}{35.41}+\frac{9}{41.50}+\frac{7}{50.57}\)
\(\frac{A}{5}=\frac{1}{31}-\frac{1}{35}+\frac{1}{35}-\frac{1}{41}+\frac{1}{41}-\frac{1}{50}+\frac{1}{50}-\frac{1}{57}\)
\(\frac{A}{5}=\frac{1}{31}-\frac{1}{57}\)
\(\Rightarrow A=5\left(\frac{1}{31}-\frac{1}{57}\right)=\frac{130}{1767}\)
c] Ta đặt \(\left(8n+5,6n+4\right)=d\)
\(\Rightarrow\frac{8n+5\div d}{6n+4\div d}\Rightarrow4\times\left(6n+4\right)-3\times\left(8n+5\right)=\left(24n+16\right)-\left(24n+15\right):d\)\(\Rightarrow d=1\)
Vậy \(\frac{8n+5}{6n+4}\)là phân số tối giản
Ai giải giúp mấy bài toán vs
Bài 1:
A=\(\sqrt{\frac{1}{\text{√}2+1}-\frac{\text{√}8-\text{√}10}{2-\text{√}5}}\)
B=\(\frac{5\text{√}5}{\text{√}5+2}+\frac{\text{√}5}{\text{√}5-1}-\frac{3\text{√}5}{3+\text{√}5}\)
Bài 2 rút gọn biểu thức
A=\(\left(\frac{x+\sqrt[]{xy}}{\text{√}x+\text{√}y}-2\right):\frac{1}{\text{√}x+2}\) với x :y >0
B=\(\left(\frac{a}{a-2\text{√}a}+\frac{a}{\text{√}a-2}\right):\frac{\text{√}a+1}{a-4\text{√}a+4}\)
Bài 3 cho biểu thức
P=\(\left(\frac{x-2}{x+2\text{√}x}+\frac{1}{\text{√}x+2}\right)\frac{\text{√}x+1}{\text{√}x-1}\)
a)Rút gọn P
b)tìm x để P=\(\text{√}x+\frac{5}{2}\)
bài 4 rút gọn biểu thức
A=\(\frac{1}{x+\text{√}x}+\frac{2\text{√}x}{x-1}-\frac{1}{x-\text{√}x}\)
B=\(\left(\frac{x}{x+3\text{√}x}+\frac{1}{\text{√}x+3}\right):\left(1-\frac{2}{\text{√}x}+\frac{6}{x+3\text{√}x}\right)\)
Bài 5
A=\(\left(\frac{2}{\text{√}x-3}-\frac{1}{\text{√}x+3}-\frac{x}{\text{√}x\left(x-9\right)}\right):\text{(√}x+3-\frac{x}{\text{√}x-3}\)
a)rút gọn A
b)tìm gtri x để A= -1/4
AI GIẢI GIÙM MÌNH ĐI MÌNH TẠ ƠN
tinh nhanh
\(\frac{4}{3\text{x}7}\)+ \(\frac{5}{7\text{x}12}\)+ \(\frac{1}{12\text{x}13}\)+ \(\frac{7}{13\text{x}20}\)+ \(\frac{3}{20\text{x}23}\)+ \(\frac{6}{23\text{x}29}\)
Tìm x: ( ai làm xong trước, mình sẽ tick cho )
\(\frac{x}{-2}=\frac{-8}{x}\)\(\frac{-5}{x}=\frac{20}{28}\)\(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)\(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)\(\frac{3}{x-5}=\frac{-4}{x+2}\)1.Vì \(\frac{x}{-2}=\frac{-8}{x}\Rightarrow-2.\left(-8\right)=x.x\)
\(16=x.x\)hay \(4^2=x^2\Rightarrow x=4\)
2. Rút gọn : \(\frac{20}{28}=\frac{5}{7}=\frac{-5}{-7}\)
\(\Rightarrow x=-7\)
3. \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)
\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
Mà \(\frac{8}{7}+\frac{11}{5}=\frac{502}{35}\)
\(\Rightarrow x=\frac{234}{35}\)
1) \(\frac{x}{-2}=\frac{-8}{x}\)
\(\Rightarrow x\times x=\left(-2\right)\times\left(-8\right)\)
\(\Rightarrow x^2=16\)
\(\Rightarrow\orbr{\begin{cases}x^2=4^2\\x^2=\left(-4\right)^2\end{cases}\Rightarrow}\orbr{\begin{cases}x=4\\x=-4\end{cases}}\)
Vậy x = 4 hoặc x = -4
2) \(\frac{-5}{x}=\frac{20}{28}\)
\(\Rightarrow\frac{-5}{x}=\frac{5}{7}\)
\(\Rightarrow5\times x=\left(-5\right)\times7\)
\(\Rightarrow5\times x=-35\)
\(\Rightarrow x=\left(-35\right):5\)
\(\Rightarrow x=-7\)
Vậy x = -7
3) \(\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)
\(\Rightarrow\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
\(\Rightarrow\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)
\(\Rightarrow\frac{x}{2}=\frac{117}{35}\)
\(\Rightarrow35x=117\times2\)
\(\Rightarrow35x=234\)
\(\Rightarrow x=234:35\)
\(\Rightarrow x=\frac{234}{35}\)
Vậy \(x=\frac{234}{35}\)
4) \(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)
\(\Rightarrow\frac{x}{5}+\frac{9}{2}=\frac{9}{14}\)
\(\Rightarrow\frac{x}{5}=\frac{9}{14}-\frac{9}{2}\)
\(\Rightarrow\frac{x}{5}=\frac{-27}{7}\)
\(\Rightarrow7x=\left(-27\right)\times5\)
\(\Rightarrow7x=-135\)
\(\Rightarrow x=\left(-135\right):7\)
\(\Rightarrow x=\frac{-135}{7}\)
Vậy \(x=\frac{-135}{7}\)
5) \(\frac{3}{x-5}=\frac{-4}{x+2}\)
\(\Rightarrow\frac{3}{x-5}+\frac{4}{x+2}=0\)
\(\Rightarrow3\left(x+2\right)+4\left(x-5\right)=0\)
\(\Rightarrow3x+6+4x-20=0\)
\(\Rightarrow\left(3x+4x\right)+\left(6-20\right)=0\)
\(\Rightarrow7x-14=0\)
\(\Rightarrow7x=14\)
\(\Rightarrow x=14:7\)
\(\Rightarrow x=2\)
Vậy x = 2
_Chúc bạn học tốt_
\(1.\frac{x}{-2}=\frac{-8}{x}\)
\(\Rightarrow x\times x=\left(-8\right)\times\left(-2\right)\)
\(x^2=16\)
\(\Rightarrow x=4\)
Vậy\(x=4\)
\(2.\frac{-5}{x}=\frac{20}{28}\)
\(\frac{-5}{x}=\frac{5}{7}\)
\(\frac{-5}{x}=\frac{-5}{-7}\)
\(\Rightarrow x=-7\)
Vậy\(x=-7\)
\(3.\frac{x}{2}-\frac{11}{5}=\frac{7}{8}\times\frac{64}{49}\)
\(\frac{x}{2}-\frac{11}{5}=\frac{8}{7}\)
\(\frac{x}{2}=\frac{8}{7}+\frac{11}{5}\)
\(\frac{x}{2}=\frac{40+77}{35}\)
\(\frac{x}{2}=\frac{117}{35}\)
\(x\times35=117\times2\)
\(35x=234\)
\(x=\frac{234}{35}\)
Vậy\(x=\frac{234}{35}\)
\(4.\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{36}{48}\)
\(\frac{x}{5}+\frac{9}{2}=\frac{6}{7}\times\frac{3}{4}\)
\(\frac{x}{5}+\frac{9}{2}=\frac{9}{14}\)
\(\frac{x}{5}=\frac{9}{14}-\frac{9}{2}\)
\(\frac{x}{5}=\frac{9}{14}-\frac{63}{14}\)
\(\frac{x}{5}=\frac{-54}{14}\)
\(\frac{x}{5}=\frac{-27}{7}\)
\(7x=\left(-27\right)\times5\)
\(7x=-135\)
\(x=\frac{-135}{7}\)
Vậy\(x=\frac{-135}{7}\)
\(5.\frac{3}{x-5}=\frac{-4}{x+2}\)
\(3\times\left(x+2\right)=\left(-4\right)\times\left(x-5\right)\)
\(3x+6=\left(-4\right)x+20\)
\(3x+4x=20-6\)
\(7x=14\)
\(x=14\div7\)
\(x=2\)
Vậy\(x=2\)
Thực hiện phép tính
a) \(\frac{\text{x + 9}}{x^2 - 9}-\frac{\text{3}}{\text{x^2 + 3x}}\)
b) \(\frac{\text{3x + 5 }}{\text{x^2 - 5x }}+\frac{\text{ 25 - x }}{\text{25 - 5x }}\)
c) \(\frac{\text{3 }}{\text{2x }}+\frac{\text{3x - 3 }}{\text{2x - 1 }}+\frac{ 2x^2 + 1 }{\text{4x^2 - 2x }}\)
d) \(\frac{\text{1}}{\text{3x - 2 }}-\frac{1}{\text{3x + 2 }}- \frac{\text{3x - 6}}{\text{4 - 9x^2}}\)
e) \(\frac{\text{18 }}{\text{(x - 3)(x^2 - 9) }}-\frac{\text{3 }}{\text{x^2 - 6x + 9 }}-\frac{\text{x}}{\text{x^2 - 9}}\)
g) \(\frac{\text{x + 2 }}{\text{x + 3 }}-\frac{\text{5 }}{\text{x^2 + x - 6 }}+\frac{\text{1}}{\text{2 - x}}\)
h) \(\frac{\text{4x }}{\text{x + 2 }}-\frac{\text{3x }}{\text{x - 2 }}+\frac{\text{12x}}{\text{x^2 - 4}}\)
i) \(\frac{\text{ x + 1 }}{\text{ x - 1 }}-\frac{\text{ x - 1 }}{\text{ x + 1 }}-\frac{\text{4}}{\text{1 - x^2}}\)
k) \(\frac{\text{
3x + 21
}}{\text{
x^2 - 9
}}+\frac{\text{2 }}{\text{x + 3 }}-\frac{\text{3}}{\text{x - 3}}\)
Tìm x,y biết \(\text{}\text{}\frac{x+5}{4x+3}=\frac{10-x}{3y-6}=\frac{8x-9}{4x+3y-3}\)
Nhớ trình bày
Ai nhanh nhất mình tick cho
\(\frac{x+5}{4x+3}=\frac{10-x}{3y-6}=\frac{x+5+10-x}{4x+3+3y-6}=\frac{15}{4x+3y-3}=\frac{8x-9}{4x+3y-3}\)
\(\Rightarrow8x-9=15\Rightarrow x=3\)
Tìm x
a, \(\text{|}x+\frac{1}{2}\text{|}-\frac{2}{3}=\sqrt{\frac{16}{9}}\)
b,\(3,5-\text{|}x+\frac{2}{3}\text{|}=\frac{4}{5}\)
c, \(3^5.x=3^{12}\)
d, \(2\frac{2}{3}:x=1\frac{7}{9}:2\)
e, \(7-\text{|}\frac{2}{3}+\text{x|=\sqrt{\frac{9}{4}}}\)
trình bày cách làm nữa nha . làm được bao nhêu thì giúp mình bấy nhiêu nha . không cần làm dược hết
Mấy cái này là bài tìm x mày mò một tẹo là ra mà. Câu a thì tính ra được căn bậc 2 của 16/9 là 4/3. Sẽ tính ra được giá trị tuyệt đối của x + 1/2. Từ đó suy ra 2 trường hợp. Làm tương tự với câu b.
Câu c tính ra được x bằng 3 mũ 7 (3^12 / 3^5 = 3^7)
Câu d đổi hỗn số ra phân số rồi làm như bình thường.