\(A=\left(2\cdot\dfrac{8}{11}-1\cdot\dfrac{-5}{11}\right)^2=\left(\dfrac{16}{11}+\dfrac{5}{11}\right)^2=\left(\dfrac{21}{11}\right)^2=\dfrac{441}{121}\)
\(B=\left(4+1\right)\left(\dfrac{64}{121}+\dfrac{25}{121}\right)=5\cdot\dfrac{89}{121}\)
mà \(441< 5\cdot89\)
nên A<B
Tìm x thuộc N biết rằng:
a/\(8< 2^x\)bé bằng\(2^6.2^{-2}\)
b/\(\left(\dfrac{2}{5}\right)^x>\left(\dfrac{5}{2}\right)^{-3}.\left(-\dfrac{2}{5}\right)^2\)
1: Tính hợp lí:
a, \(\dfrac{11}{125}\)- \(\dfrac{17}{18}-\dfrac{5}{7}+\dfrac{4}{9}\)+ \(\dfrac{17}{14}\)
b,\(-1\dfrac{5}{7}.15+\dfrac{2}{7}.\left(-15\right)+\left(-105\right).\left(\dfrac{2}{3}-\dfrac{4}{5}+\dfrac{1}{7}\right)\)
2: Tìm x:
a, \(\dfrac{11}{13}-\left(\dfrac{5}{42}-x\right)=-\left(\dfrac{15}{28}-\dfrac{11}{13}\right)\)
b,\(|x+\dfrac{4}{15}|-|-3,75|=-|-2,15|\)
c, \(^{7^{x+2}}+2.7^{x-1}=345\)
Tìm x,y:
a/\(x^2+\left(y-\dfrac{1}{10}\right)^4=0\)
b/\(\left(\dfrac{1}{2}x-5\right)^{20}+\left(y^2-\dfrac{1}{4}\right)^{10}\le0\)
1)Tìm x;y;z biết
a) \(\dfrac{x-1}{2}=\dfrac{y-2}{3}=\dfrac{z-3}{4}\) và \(2x+3y-z=50\)
2)Cho \(x\ne0;y\ne0;z\ne0\) và \(x-y-z=0\)
Tính:\(B=\left(1-\dfrac{z}{x}\right).\left(1-\dfrac{x}{y}\right).\left(1+\dfrac{y}{z}\right)\)
Tìm x:
\(\dfrac{x}{-18}=\dfrac{-50}{x};\\ 1\dfrac{1}{3}:\left(-0,08\right)=\dfrac{2}{3}:\left(-0,1x\right);\\ x=\dfrac{a}{b+c}=\dfrac{b}{c+a}=\dfrac{c}{b+a};\\ \dfrac{x^2}{6}=\dfrac{24}{25};\dfrac{x+1}{x-5}=\dfrac{0,5}{0,6};\\ \dfrac{2}{3}x:\dfrac{1}{5}=1\dfrac{1}{3}:\dfrac{1}{4};\\ 1,35:0,2=1,25:0,1x\)
Tìm x:
a/\(\left(5x+1\right)^2=\dfrac{36}{49}\)
b/\(\left(x-\dfrac{2}{9}\right)^3=\left(\dfrac{2}{3}\right)^6\)
c/\(\left(8x+1\right)^{2n+1}=5^{2n+1}\left(n\in N\right)\)
Tính:
a/\(4^{11}:2^{10}:2^{11}\)
b/\(\dfrac{11.2^{11}-10.4^5}{16^3}\)
c/\(\left(2^5+14.2^4\right):2^3\)
d/\(A=12.\left(-\dfrac{2}{3}\right)^2+\dfrac{4}{3}\)
Tìm x:
a/\(\left(\dfrac{12}{25}\right)^x\)=\(\left(\dfrac{3}{5}\right)^2-\left(-\dfrac{3}{5}\right)^4\)
b/\(\left(-\dfrac{3}{4}\right)^{3x-1}=\dfrac{256}{81}\)
c/172\(x^2-7^9:98^3=2^{-3}\)
Tìm \(x\in Z\),biết:
a/\(x^2=16\)
b/\(x^3=-8\)
c/\(\left(x+2\right)^2=4\)
d/\(\left(1-x\right)^3=1\)
e/\(\dfrac{1}{4}.\dfrac{1}{6}.\dfrac{3}{8}.\dfrac{4}{10}.....\dfrac{14}{30}.\dfrac{15}{32}=2^x\)
