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a, (x2 - 5)(x2 - 24) < 0
=> x2 - 5 và x2 - 24 trái dấu
Mà x2 - 5 > x2 - 24 => \(\hept{\begin{cases}x^2-5>0\\x^2-24>0\end{cases}\Rightarrow5< x^2< 24}\)
Vì x \(\in\)Z nên x2 = 9;16
+) x2 = 9 => x = 3 hoặc x = -3
+) x2 = 16 => x = 4 hoặc x = -4
Vậy...
b,
\(\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}=\frac{x+1}{13}+\frac{x+1}{14}\)
\(\Rightarrow\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}-\frac{x+1}{13}-\frac{x+1}{14}=0\)
\(\Rightarrow\left(x+1\right)\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)
Mà \(\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)\ne0\)
=> x + 1 = 0 => x = 0 - 1 => x = -1
\(\frac{x+1}{14}+\frac{x+2}{13}=\frac{x+3}{12}+\frac{x+4}{11}\)
\(\Rightarrow\left(\frac{x+1}{14}+1\right)+\left(\frac{x+2}{13}+1\right)=\left(\frac{x+3}{12}+1\right)+\left(\frac{x+4}{11}+1\right)\)
\(\Rightarrow\frac{x+15}{14}+\frac{x+15}{13}=\frac{x+15}{12}+\frac{x+15}{11}\)
\(\Rightarrow\frac{x+15}{14}+\frac{x+15}{13}-\frac{x+15}{12}-\frac{x+15}{11}=0\)
\(\Rightarrow\left(x+15\right)\left(\frac{1}{14}+\frac{1}{13}-\frac{1}{12}-\frac{1}{11}\right)=0\)
Mà \(\left(\frac{1}{14}+\frac{1}{13}-\frac{1}{12}-\frac{1}{11}\right)\ne0\)
=> x + 15 = 0 => x = 0 - 15 => x = -15
Ta có:
4116 / 10290 = 7.7.7.712 - 7.2 / 7.7.7.7 30-7.5
= 12-2 / 30-5
= 10 / 25
= 2 / 5
nhớ k cho mình nha
A=4102/10255<=>2051*2/2051*5<=>A=2/5
B=2828/4242<=>1414*2/1414*3<=>B=2/3
ủng hộ nha mn
\(\frac{x}{5}\le\frac{12}{x}\Rightarrow x^2\le60\left(1\right)\)
\(\frac{12}{x}\le\frac{x}{3}\Rightarrow x^2\ge36\left(2\right)\)
Từ (1) và (2)
\(\Rightarrow36\le x^2\le60\) và \(x\in N\)
\(\Rightarrow6\le x\le7,75\)
Vậy \(x=6;7\)
Ta có:-2/4=x/10=>4.x=-2.10=>4.x=-20=>x=-20:4=>x=-5
Thay x=-5 ta có:-5/10=-7/y=>10.(-7)=y.(-5)=>y.(-5)=-70=>y=-70:(-5)=>y=14
Thay y=14 ta có:-7/14=z/-24=>14.z=-24.(-7)=>14.z=168=>z=168:14=>z=12
Vậy x=-5;y=14;z=12
Đúng 100% luôn nha!
\(H=\frac{4116-14}{10290-35}=\frac{14.294-14}{35.294-35}=\frac{14.\left(294-1\right)}{35.\left(294-1\right)}=\frac{14.293}{35.293}=\frac{2}{5}\)
\(K=\frac{29.101-101}{2.19.101+4.101}=\frac{101.\left(29-1\right)}{101.\left(38+4\right)}=\frac{28}{42}=\frac{2}{3}\)
\(I=\frac{1313-1717}{303}=\frac{13.101-17.101}{3.101}=\frac{101.\left(13-17\right)}{3.101}=\frac{-4}{3}\)
\(M=\frac{12-24.3}{1-35}=\frac{12-12.2.3}{-34}=\frac{12.\left(1-6\right)}{-34}=\frac{-60}{-34}=\frac{30}{17}\)
\(H\)\(=\) \(\frac{4116-14}{10290-35}\)
\(=\) \(\frac{4102}{10255}\)
\(=\) \(\frac{4102:2051}{10255:2051}\)
\(=\) \(\frac{2}{5}\)
\(K=\frac{2929-101}{2.1919+404}\)
\(=\) \(\frac{2828}{4242}\)
\(=\) \(\frac{2828:1414}{4242:1414}\)
\(=\) \(\frac{2}{3}\)
\(M=\frac{12-24.3}{1-35}\)
\(=\) \(\frac{-60}{-34}\)
\(=\) \(\frac{60}{34}\)
\(=\) \(\frac{30}{17}\)
:D
A=\(\frac{14.294-14}{35.294-35}=\frac{14.\left(294-1\right)}{35.\left(294-1\right)}=\frac{14}{35}=\frac{2}{5}\)
ƯCLN(4116,35)=7
ƯCLN(14,10290)=14
Nên rút gọn thành: 588-1/735-5
\(a,\left(\frac{31}{20}-\frac{26}{45}\right)\cdot\left(\frac{-36}{35}\right)< x< \left(\frac{51}{56}+\frac{8}{21}+\frac{1}{3}\right)\cdot\frac{8}{13}\)
\(taco:\left(\frac{31}{20}-\frac{26}{45}\right)\cdot\left(\frac{-36}{35}\right)=\frac{35}{36}\cdot\frac{-36}{35}=-1\)
\(\left(\frac{51}{56}+\frac{8}{21}+\frac{1}{3}\right)\cdot\frac{8}{13}=\frac{13}{8}\cdot\frac{8}{13}=1\)
\(=>x=0\)
\(b,\frac{-5}{6}+\frac{8}{3}+\frac{29}{-3}< x< \frac{-1}{2}+2+\frac{5}{2}\)(dau <co dau gach ngang o duoi nha)
\(taco:\frac{-5}{6}+\frac{8}{3}+\frac{29}{-3}=\frac{-5}{6}+\frac{8}{3}+\frac{-29}{3}=\frac{-5}{6}+\frac{16}{6}+\frac{-58}{6}=\frac{-47}{6}=-7,8\)
\(\frac{-1}{2}+2+\frac{5}{2}=\frac{3}{2}+\frac{5}{2}=4\)
tu do \(=>x=-7,8;...;0;1;2;3;4\)
\(\frac{2}{x}=\frac{x}{8}\Rightarrow x^2=16=4^2\Rightarrow\orbr{\begin{cases}x=4\\x=-4\end{cases}}\)
\(A=\frac{4116-14}{10290-35}=\frac{4102}{10255}=\frac{2}{5}\)
3, \(\frac{2}{x}\)=\(\frac{x}{8}\)
Suy ra : x . x = 2 . 8
x2 = 16
x2= 42 hoặc x2 = (-4)2
Suy ra x=4 hoặc x=-4
A=\(\frac{4116-14}{10290-35}\)=\(\frac{4102}{10255}\)=\(\frac{2}{5}\)